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Abstract:

An apparatus for processing a signal and method thereof are disclosed.
Data coding and entropy coding are performed with interconnection, and
grouping is used to enhance coding efficiency. The present invention
includes the steps of obtaining a pilot reference value corresponding to
a plurality of gains and a pilot difference value corresponding to the
pilot reference value; and obtaining the gain using the pilot reference
value and the pilot difference value.

Claims:

1. A method of processing a signal, comprising the steps of:Obtaining from
the signal a pilot reference value corresponding to a plurality of gains
and a pilot difference value corresponding to the pilot reference value;
andobtaining at least one gain from the plurality of gains using the
pilot reference value and the pilot difference value.

2. The method of claim 1, further comprising the step of decoding at least
one of the pilot difference value and the pilot reference value.

3. The method of claim 1, further comprising the step of reconstructing an
audio signal using the obtained gain.

4. The method of claim 1, wherein the pilot reference value comprises an
average of the plurality of gains or an approximate value of the average
of the plurality of gains.

5. The method of claim 1, wherein the pilot reference value comprises an
intermediate value of the plurality of gains.

6. The method of claim 1, wherein the pilot reference value comprises a
most frequently used value of the plurality of gains.

8. The method of claim 1, wherein the pilot reference value comprises one
value extracted from a table.

9. The method of claim 1, further comprising the step of selecting the
gain having highest encoding efficiency as a final pilot reference value
after the pilot reference value has been set to each of a plurality of
gains.

10. An apparatus for processing a signal, comprising:a value obtaining
part configured for obtaining from the signal a pilot reference value
corresponding to a plurality of gains and a pilot difference value
corresponding to the pilot reference value; anda gain obtaining part
configured for obtaining the gain using the pilot reference value and the
pilot difference value.

11. A method of processing a signal, comprising the steps of:generating a
pilot difference value using a pilot reference value corresponding to a
plurality of gains and the gains, where in the pilot reference value is
obtained from the signal; andtransferring the generated pilot difference
value.

12. An apparatus for processing a signal, comprising:a value calculating
part configured for generating a pilot difference value using a pilot
reference value corresponding to a plurality of gains and the gains,
wherein the pilot reference value is obtained from the signal; andan
outputting part transferring the generated pilot difference value.

Description:

TECHNICAL FIELD

[0001]The present invention relates to an apparatus for processing a
signal and method thereof, and more particularly, to an apparatus for
coding data and method thereof.

BACKGROUND ART

[0002]Generally, many techniques for signal compression and recovery have
been introduced so far. And, applicable targets of the corresponding
techniques are various data including audio data, video data and the
like. Moreover, the signal compression or recovery techniques evolve in a
direction to enhancing audio or video quality with high compression
rates. Besides, many efforts have been made to raise transmission
efficiency for adaptation to various communication environments.

[0003]However, it is still believed that there exists a margin for the
enhancement of the transmission efficiency. So, many efforts need to be
made to maximize transmission efficiency of signals in the very
complicated communication environments through the development of new
processing schemes for signals.

DISCLOSURE OF THE INVENTION

[0004]Accordingly, the present invention is directed to an apparatus for
processing a signal and method thereof that substantially obviate one or
more of the problems due to limitations and disadvantages of the related
art.

[0005]An object of the present invention is to provide an apparatus for
processing a signal and method thereof, by which transmission efficiency
of signals can be optimized.

[0006]Another object of the present invention is to provide an apparatus
for coding data and method thereof, by which data can be efficiently
coded.

[0007]Another object of the present invention is to provide an apparatus
for encoding/decoding data and method thereof, by which transmission
efficiency of control data used for audio recovery can be maximized.

[0008]Another object of the present invention is to provide a medium
including encoded data.

[0009]Another object of the present invention is to provide a data
structure, by which encoded data can be efficiently transferred.

[0010]A further object of the present invention is to provide a system
including the decoding apparatus.

[0011]To achieve these and other advantages and in accordance with the
purpose of the present invention, as embodied and broadly described, a
method of processing a signal according to the present invention includes
the steps of obtaining a pilot reference value corresponding to a
plurality of gains and a pilot difference value corresponding to the
pilot reference value and obtaining the gain using the pilot reference
value and the pilot difference value.

[0012]The method further includes the step of decoding at least one of the
pilot difference value and the pilot reference value. And, The method
further includes the step of reconstructing an audio signal using the
obtained gain.

[0013]The pilot reference value is obtained from one of an average of a
plurality of the gains, an approximate value of the average, an
intermediate value of a plurality of the gains, a most frequently used
value of a plurality of the gains, a value set to a default and one value
extracted from a table.

[0014]The method further includes the step of selecting the gain having
highest encoding efficiency as a final pilot reference value after the
pilot reference value has been set to each of a plurality of the gains.

[0015]To further achieve these and other advantages and in accordance with
the purpose of the present invention, an apparatus for processing a
signal includes a value obtaining part obtaining a pilot reference value
corresponding to a plurality of gains and a pilot difference value
corresponding to the pilot reference value and a gain obtaining part
obtaining the gain using the pilot reference value and the pilot
difference value.

[0016]To further achieve these and other advantages and in accordance with
the purpose of the present invention, a method of processing a signal
includes the steps of generating a pilot difference value using a pilot
reference value corresponding to a plurality of gains and the gains and
transferring the generated pilot difference value.

[0017]To further achieve these and other advantages and in accordance with
the purpose of the present invention, an apparatus for processing a
signal including a value calculating part generating a pilot difference
value using a pilot reference value corresponding to a plurality of gains
and the gains and an outputting part transferring the generated pilot
difference value.

[0019]FIG. 1 and FIG. 2 are block diagrams of a system according to the
present invention;

[0020]FIG. 3 and FIG. 4 are diagrams to explain PBC coding according to
the present invention;

[0021]FIG. 5 is a diagram to explain types of DIFF coding according to the
present invention;

[0022]FIGS. 6 to 8 are diagrams of examples to which DIFF coding scheme is
applied;

[0023]FIG. 9 is a block diagram to explain a relation in selecting one of
at least three coding schemes according to the present invention;

[0024]FIG. 10 is a block diagram to explain a relation in selecting one of
at least three coding schemes according to a related art;

[0025]FIG. 11 and FIG. 12 are flowcharts for the data coding selecting
scheme according to the present invention, respectively;

[0026]FIG. 13 is a diagram to explaining internal grouping according to
the present invention;

[0027]FIG. 14 is a diagram to explaining external grouping according to
the present invention;

[0028]FIG. 15 is a diagram to explain multiple grouping according to the
present invention;

[0029]FIG. 16 and FIG. 17 are diagrams to explain mixed grouping according
to another embodiments of the present invention, respectively;

[0030]FIG. 18 is an exemplary diagram of 1D and 2D entropy table according
to the present invention;

[0031]FIG. 19 is an exemplary diagram of two methods for 2D entropy coding
according to the present invention;

[0032]FIG. 20 is a diagram of entropy coding scheme for PBC coding result
according to the present invention;

[0033]FIG. 21 is a diagram of entropy coding scheme for DIFF coding result
according to the present invention;

[0034]FIG. 22 is a diagram to explain a method of selecting an entropy
table according to the present invention;

[0035]FIG. 23 is a hierarchical diagram of a data structure according to
the present invention;

[0036]FIG. 24 is a block diagram of an apparatus for audio compression and
recovery according to one embodiment of the present invention;

[0037]FIG. 25 is a detailed block diagram of a spatial information
encoding part according to one embodiment of the present invention; and

[0038]FIG. 26 is a detailed block diagram of a spatial information
decoding part according to one embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0039]Reference will now be made in detail to the preferred embodiments of
the present invention, examples of which are illustrated in the
accompanying drawings.

[0040]General terminologies used currently and globally are selected as
terminologies used in the present invention. And, there are terminologies
arbitrarily selected by the applicant for special cases, for which
detailed meanings are explained in detail in the description of the
preferred embodiments of the present invention. Hence, the present
invention should be understood not with the names of the terminologies
but with the meanings of the terminologies.

[0041]In the present invention, a meaning of `coding` includes an encoding
process and a decoding process. Yet, it is apparent to those skilled in
the art that a specific coding process is applicable to an encoding or
decoding process only, which will be discriminated in the following
description of a corresponding part. And, the `coding` can be named
`codec` as well.

[0042]In the present invention, steps of coding a signal shall be
explained by being divided into data coding and entropy coding. Yet,
correlation exits between the data coding and the entropy coding, which
shall be explained in detail later.

[0044]In the present invention, an audio coding scheme (e.g., `ISO/IEC
23003, MPEG Surround`) having spatial information will be explained as a
detailed example that adopts data coding and entropy coding.

[0045]FIG. 1 and FIG. 2 are diagrams of a system according to the present
invention. FIG. 1 shows an encoding apparatus 1 and FIG. 2 shows a
decoding apparatus 2.

[0046]Referring to FIG. 1, an encoding apparatus 1 according to the
present invention includes at least one of a data grouping part 10, a
first data encoding part 20, a second data encoding part 31, a third data
encoding part 32, an entropy encoding part 40 and a bitstream
multiplexing part 50.

[0047]Optionally, the second and third data encoding parts 31 and 32 can
be integrated into one data encoding part 30. For instance, variable
length encoding is performed on data encoded by the second and third data
encoding parts 31 and 32 by the entropy encoding part 40. The above
elements are explained in detail as follows.

[0049]For instance, the data grouping part 10 discriminates data according
to data types. And, the discriminated data is encoded by one of the data
encoding parts 20, 31 and 32. The data grouping part 10 discriminates
some of data into at least one group for the data processing efficiency.
And, the grouped data is encoded by one of the data encoding parts 20, 31
and 32. Besides, a grouping method according to the present invention, in
which operations of the data grouping part 10 are included, shall be
explained in detail with reference to FIGS. 13 to 17 later.

[0050]Each of the data encoding parts 20, 31 and 32 encodes input data
according to a corresponding encoding scheme. Each of the data encoding
parts 20, 31 and 32 adopts at least one of a PCM (pulse code modulation)
scheme and a differential coding scheme. In particular, the first data
encoding part 20 adopts the PCM scheme, the second data encoding part 31
adopts a first differential coding scheme using a pilot reference value,
and the third data encoding part 32 adopts a second differential coding
scheme using a difference from neighbor data, for example.

[0051]Hereinafter, for convenience of explanation, the first differential
coding scheme is named `pilot based coding (PBC)` and the second
differential coding scheme is named `differential coding (DIFF)`. And,
operations of the data encoding parts 20, 31 and 32 shall be explained in
detail with reference to FIGS. 3 to 8 later.

[0052]Meanwhile, the entropy encoding part 40 performs variable length
encoding according to statistical characteristics of data with reference
to an entropy table 41. And, operations of the entropy encoding part 40
shall be explained in detail with reference to FIGS. 18 to 22 later.

[0053]The bitstream multiplexing part 50 arranges and/or coverts the coded
data to correspond to a transfer specification and then transfers the
arranged/converted data in a bitstream form. Yet, if a specific system
employing the present invention does not use the bitstream multiplexing
part 50, it is apparent to those skilled in the art that the system can
be configured without the bitstream multiplexing part 50.

[0054]Meanwhile, the decoding apparatus 2 is configured to correspond to
the above-explained encoding apparatus 1.

[0055]For instance, referring to FIG. 2, a bitstream demultiplexing part
60 receives an inputted bitstream and interprets and classifies various
information included in the received bitstream according to a preset
format.

[0056]An entropy decoding part 70 recovers the data into the original data
before entropy encoding using an entropy table 71. In this case, it is
apparent that the entropy table 71 is identically configured with the
former entropy table 41 of the encoding apparatus 1 shown in FIG. 1.

[0057]A first data decoding part 80, a second data decoding part 91 and a
third data decoding part 92 perform decoding to correspond to the
aforesaid first to third data encoding parts 20, 31 and 32, respectively.

[0058]In particular, in case that the second and third data decoding parts
91 and 92 perform differential decoding, it is able to integrate
overlapped decoding processes to be handled within one decoding process.

[0059]A data reconstructing part 95 recovers or reconstructs data decoded
by the data decoding parts 80, 91 and 92 into original data prior to data
encoding. Occasionally, the decoded data can be recovered into data
resulting from converting or modifying the original data.

[0060]By the way, the present invention uses at least two coding schemes
together for the efficient execution of data coding and intends to
provide an efficient coding scheme using correlation between coding
schemes.

[0061]And, the present invention intends to provide various kinds of data
grouping schemes for the efficient execution of data coding.

[0062]Moreover, the present invention intends to provide a data structure
including the features of the present invention.

[0063]In applying the technical idea of the present invention to various
systems, it is apparent to those skilled in the art that various
additional configurations should be used as well as the elements shown in
FIG. 1 and FIG. 2. For example, data quantization needs to be executed or
a controller is needed to control the above process.

[Data Coding]

[0064]PCM (pulse code modulation), PBC (pilot based coding) and DIFF
(differential coding) applicable as data coding schemes of the present
invention are explained in detail as follows. Besides, efficient
selection and correlation of the data coding schemes shall be
subsequently explained as well.

[0065]1. PCM (Pulse Code Modulation)

[0066]PCM is a coding scheme that converts an analog signal to a digital
signal. The PCM samples analog signals with a preset interval and then
quantizes a corresponding result. PCM may be disadvantageous in coding
efficiency but can be effectively utilized for data unsuitable for PBC or
DIFF coding scheme that will be explained later.

[0067]In the present invention, the PCM is used together with the PBC or
DIFF coding scheme in performing data coding, which shall be explained
with reference to FIGS. 9 to 12 later.

[0068]2. PBC (Pilot Based Coding)

[0069]2-1. Concept of PBC

[0070]PBC is a coding scheme that determines a specific reference within a
discriminated data group and uses the relation between data as a coding
target and the determined reference.

[0071]A value becoming a reference to apply the PBC can be defined as
`reference value`, `pilot`, `pilot reference value` or `pilot value`.
Hereinafter, for convenience of explanation, it is named `pilot reference
value`.

[0072]And, a difference value between the pilot reference value and data
within a group can be defined as `difference` or `pilot difference`.

[0073]Moreover, a data group as a unit to apply the PBC indicates a final
group having a specific grouping scheme applied by the aforesaid data
grouping part 10. Data grouping can be executed in various ways, which
shall be explained in detail later.

[0074]In the present invention, data grouped in the above manner to have a
specific meaning is defined as `parameter` to explain. This is just for
convenience of explanation and can be replaced by a different
terminology.

[0075]The PBC process according to the present invention includes at least
two steps as follows.

[0076]First of all, a pilot reference value corresponding to a plurality
of parameters is selected. In this case, the pilot reference value is
decided with reference to a parameter becoming a PBC target.

[0077]For instance, a pilot reference value is set to a value selected
from an average value of parameters becoming PBC targets, an approximate
value of the average value of the parameters becoming the targets, an
intermediate value corresponding to an intermediate level of parameters
becoming targets and a most frequently used value among parameters
becoming targets. And, a pilot reference value can be set to a preset
default value as well. Moreover, a pilot value can be decided by a
selection within a preset table.

[0078]Alternatively, in the present invention, temporary pilot reference
values are set to pilot reference values selected by at least two of the
various pilot reference value selecting methods, coding efficiency is
calculated for each case, the temporary pilot reference value
corresponding to a case having best coding efficiency is then selected as
a final pilot reference value.

[0079]The approximate value of the average is Ceil[P] or Floor[P] when the
average is P. In this case, Ceil[x] is a maximum integer not exceeding
`x` and Floor[x] is a minimum integer exceeding `x`.

[0080]Yet, it is also possible to select an arbitrary fixed default value
without referring to parameters becoming PBC targets.

[0081]For another instance, as mentioned in the foregoing description,
after several values selectable as pilots have been randomly and plurally
selected, a value showing the best coding efficiency can be selected as
an optimal pilot.

[0082]Secondly, a difference value between the selected pilot and a
parameter within a group is found. For instance, a difference value is
calculated by subtracting a pilot reference value from a parameter value
becoming a PBC target. This is explained with reference to FIG. 2 and
FIG. 4 as follows.

[0083]FIG. 3 and FIG. 4 are diagrams to explain PBC coding according to
the present invention.

[0084]For instance, it is assumed that a plurality of parameters (e.g., 10
parameters) exist within one group to have the following parameter
values, X[n]={11, 12, 9, 12, 10, 8, 12, 9, 10, 9}, respectively.

[0085]If a PBC scheme is selected to encode the parameters within the
group, a pilot reference value should be selected in the first place. In
this example, it can be seen that the pilot reference value is set to
`10` in FIG. 4.

[0086]As mentioned in the foregoing description, it is able to select the
pilot reference value by the various methods of selecting a pilot
reference value.

[0087]Difference values by PBC are calculated according to Formula 1.

d[n]=x[n]-P, where n=0, 1, . . . , 9. [Formula 1]

[0088]In this case, `P` indicates a pilot reference value (=10) and x[n]
is a target parameter of data coding.

[0089]A result of PBC according to Formula 1 corresponds to d[n]={1, 2,
-1, 2, 0, -2, 2, -1, 0, -1}. Namely, the result of PBC coding includes
the selected pilot reference value and the calculated d[n]. And, these
values become targets of entropy coding that will be explained later.
Besides, the PBC is more effective in case that deviation of target
parameter values is small overall.

[0090]2-2. PBC Objects

[0091]A target of PBC coding is not specified into one. It is possible to
code digital data of various signals by PBC. For instance, it is
applicable to audio coding that will be explained later. In the present
invention, additional control data processed together with audio data is
explained in detail as a target of PBC coding.

[0092]The control data is transferred in addition to a downmixed signal of
audio and is then used to reconstruct the audio. In the following
description, the control data is defined as `spatial information or
spatial parameter`.

[0094]In particular, the CLD is a parameter that indicates an energy
difference between two different channels. For instance, the CLD has a
value ranging between -15 and +15. The ICC is a parameter that indicates
a correlation between two different channels. For instance, the ICC has a
value ranging between 0 and 7. And, the CPC is a parameter that indicates
a prediction coefficient used to generate three channels from two
channels. For instance, the CPC has a value ranging between -20 and 30.

[0095]As a target of PBC coding, a gain value used to adjust a gain of
signal, e.g., ADG (arbitrary downmix gain) can be included.

[0096]And, ATD (arbitrary tree data) applied to an arbitrary channel
conversion box of a downmixed audio signal can become a PBC coding
target. In particular, the ADG is a parameter that is discriminated from
the CLD, ICC or CPC. Namely, the ADG corresponds to a parameter to adjust
a gain of audio to differ from the spatial information such as CLD, ICC
CPC and the like extracted from a channel of an audio signal. Yet, for
example of use, it is able to process the ADG or ATD in the same manner
of the aforesaid CLD to raise efficiency of audio coding.

[0097]As another target of PBC coding, a partial parameter can be taken
into consideration. In the present invention, `partial parameter` means a
portion of parameter.

[0098]For instance, assuming that a specific parameter is represented as n
bits, the n bits are divided into at least two parts. And, it is able to
define the two parts as first and second partial parameters,
respectively. In case of attempting to perform PBC coding, it is able to
find a difference value between a first partial parameter value and a
pilot reference value. Yet, the second partial parameter excluded in the
difference calculation should be transferred as a separate value.

[0099]In more particular, for instance, in case of n bits indicating a
parameter value, a least significant bit (LSB) is defined as the second
partial parameter and a parameter value constructed with the rest (n-1)
upper bits can be defined as the first partial parameter. In this case,
it is able to perform PBC on the first partial parameter only. This is
because coding efficiency can be enhanced due to small deviations between
the first partial parameter values constructed with the (n-1) upper bits.

[0100]The second partial parameter excluded in the difference calculation
is separately transferred, and is then taken into consideration in
reconstructing a final parameter by a decoding part. Alternatively, it is
also possible to obtain a second partial parameter by a predetermined
scheme instead of transferring the second partial parameter separately.

[0101]PBC coding using characteristics of the partial parameters is
restrictively utilized according to a characteristic of a target
parameter.

[0102]For instance, as mentioned in the foregoing description, deviations
between the first partial parameters should be small. If the deviation is
big, it is unnecessary to utilize the partial parameters. It may even
degrade coding efficiency.

[0103]According to an experimental result, the CPC parameter of the
aforesaid spatial information is suitable for the application of the PBC
scheme. Yet, it is not preferable to apply the CPC parameter to coarse
quantization scheme. In case that a quantization scheme is coarse, a
deviation between first partial parameters increases.

[0104]Besides, the data coding using partial parameters is applicable to
DIFF scheme as well as PBC scheme.

[0105]In case of applying the partial parameter concept to the CPC
parameter, a signal processing method and apparatus for reconstruction
are explained as follows.

[0106]For instance, a method of processing a signal using partial
parameters according to the present invention includes the steps of
obtaining a first partial parameter using a reference value corresponding
to the first partial parameter and a difference value corresponding to
the reference value and deciding a parameter using the first partial
parameter and a second partial parameter.

[0107]In this case, the reference value is either a pilot reference value
or a difference reference value. And, the first partial parameter
includes partial bits of the parameter and the second partial parameter
includes the rest bits of the parameter. Moreover, the second partial
parameter includes a least significant bit of the parameter.

[0108]The signal processing method further includes the step of
reconstructing an audio signal using the decided parameter.

[0109]The parameter is spatial information including at least one of CLD,
ICC, CPC and ADG.

[0110]If the parameter is the CPC and if a quantization scale of the
parameter is not coarse, it is able to obtain the second partial
parameter.

[0111]And, a final parameter is decided by twice multiplying the partial
parameter and adding the multiplication result to the second partial
parameter.

[0112]An apparatus for processing a signal using partial parameters
according to the present invention includes a first parameter obtaining
part obtaining a first partial parameter using a reference value
corresponding to the first partial parameter and a difference value
corresponding to the reference value and a parameter deciding part
deciding a parameter using the first partial parameter and a second
partial parameter.

[0113]The signal processing apparatus further includes a second parameter
obtaining part obtaining the second partial parameter by receiving the
second partial parameter.

[0114]And, the first parameter obtaining part, the parameter deciding part
and the second partial parameter obtaining part are included within the
aforesaid data decoding part 91 or 92.

[0115]A method of processing a signal using partial parameters according
to the present invention includes the steps of dividing a parameter into
a first partial parameter and a second partial parameter and generating a
difference value using a reference value corresponding to the first
partial parameter and the first partial parameter.

[0116]And, the signal processing method further includes the step of
transferring the difference value and the second partial parameter.

[0117]An apparatus for processing a signal using partial parameters
according to the present invention includes a parameter dividing part
dividing a parameter into a first partial parameter and a second partial
parameter and a difference value generating part generating a difference
value using a reference value corresponding to the first partial
parameter and the first partial parameter.

[0118]And, the signal processing apparatus further includes a parameter
outputting part transferring the difference value and the second partial
parameter.

[0119]Moreover, the parameter diving part and the difference value
generating part are included within the aforesaid data encoding part 31
or 32.

[0120]2-3. PBC Conditions

[0121]In aspect that PBC coding of the present invention selects a
separate pilot reference value and then has the selected pilot reference
value included in a bitstream, it is probable that transmission
efficiency of the PBC coding becomes lower than that of a DIFF coding
scheme that will be explained later.

[0123]If the number of data experimentally becoming targets of data coding
within a group is at least three or higher, PBC coding is applicable.
This corresponds to a result in considering efficiency of data coding. It
means that DIFF or PCM coding is more efficient than PBC coding if two
data exist within a group only.

[0124]Although PBC coding is applicable to at least three or more data, it
is preferable that PBC coding is applied to a case that at least five
data exist within a group. In other words, a case that PBC coding is most
efficiently applicable is a case that there are at least five data
becoming targets of data coding and that deviations between the at least
five data are small. And, a minimum number of data suitable for the
execution of PBC coding will be decided according to a system and coding
environment.

[0125]Data becoming a target of data coding is given for each data band.
This will be explained through a grouping process that will be described
later. So, for example, the present invention proposes that at least five
data bands are required for the application of PBC coding in MPEG audio
surround coding that will be explained later.

[0126]Hereinafter, a signal processing method and apparatus using the
conditions for the execution of PBC are explained as follows.

[0127]In a signal processing method according to one embodiment of the
present invention, if the number of data corresponding to a pilot
reference value is obtained and if the number of data bands meets a
preset condition, the pilot reference value and a pilot difference value
corresponding to the pilot reference value are obtained. Subsequently,
the data are obtained using the pilot reference value and the pilot
difference value. In particular, the number of the data is obtained using
the number of the data bands in which the data are included.

[0128]In a signal processing method according to another embodiment of the
present invention, one of a plurality of data coding schemes is decided
using the number of data and the data are decoded according to the
decided data coding scheme. A plurality of the data coding schemes
include a pilot coding scheme at least. If the number of the data meets a
preset condition, the data coding scheme is decided as the pilot coding
scheme.

[0129]And, the data decoding process includes the steps of obtaining a
pilot reference value corresponding to a plurality of the data and a
pilot difference value corresponding to the pilot reference value and
obtaining the data using the pilot reference value and the pilot
difference value.

[0130]Moreover, in the signal processing method, the data are parameters.
And, an audio signal is recovered using the parameters. In the signal
processing method, identification information corresponding to the number
of the parameters is received and the number of the parameters is
generated using the received identification information. By considering
the number of the data, identification information indicating a plurality
of the data coding schemes is hierarchically extracted.

[0131]In the step of extracting the identification information, a first
identification information indicating a first data coding scheme is
extracted and a second identification information indicating a second
data coding scheme is then extracted using the first identification
information and the number of the data. In this case, the first
identification information indicates whether it is a DIFF coding scheme.
And, the second identification information indicates whether it is a
pilot coding scheme or a PCM grouping scheme.

[0132]In a signal processing method according to another embodiment of the
present invention, if the number of a plurality of data meets a preset
condition, a pilot difference value is generated using a pilot reference
value corresponding to a plurality of the data and the data. The
generated pilot difference value is then transferred. In the signal
processing method, the pilot reference value is transferred.

[0133]In a signal processing method according to a further embodiment of
the present invention, data coding schemes are decided according to the
number of a plurality of data. The data are then encoded according to the
decided data coding schemes. In this case, a plurality of the data coding
schemes include a pilot coding scheme at least. If the number of the data
meets a preset condition, the data coding scheme is decided as the pilot
coding scheme.

[0134]An apparatus for processing a signal according to one embodiment of
the present invention includes a number obtaining part obtaining a number
of data corresponding to a pilot reference value, a value obtaining part
obtaining the pilot reference value and a pilot difference value
corresponding to the pilot reference value if the number of the data
meets a preset condition, and a data obtaining part obtaining the data
using the pilot reference value and the pilot difference value. In this
case, the number obtaining part, the value obtaining part and the data
obtaining part are included in the aforesaid data decoding part 91 or 92.

[0135]An apparatus for processing a signal according to another embodiment
of the present invention includes a scheme deciding part deciding one of
a plurality of data coding schemes according to a number of a plurality
of data and a decoding part decoding the data according to the decided
data coding scheme. In this case, a plurality of the data coding schemes
include a pilot coding scheme at least.

[0136]An apparatus for processing a signal according to a further
embodiment of the present invention includes a value generating part
generating a pilot difference value using a pilot reference value
corresponding to a plurality of data and the data if a number of a
plurality of the data meets a preset condition and an output part
transferring the generated pilot difference value. In this case, the
value generating part is included in the aforesaid data encoding part 31
or 32.

[0137]An apparatus for processing a signal according to another further
embodiment of the present invention includes a scheme deciding part
deciding a data coding scheme according to a number of a plurality of
data and an encoding part encoding the data according to the decided data
coding scheme. In this case, a plurality of the data coding schemes
include a pilot coding scheme at least.

[0138]2-4. PBC Signal Processing Method

[0139]A signal processing method and apparatus using PBC coding features
according to the present invention are explained as follows.

[0140]In a signal processing method according to one embodiment of the
present invention, a pilot reference value corresponding to a plurality
of data and a pilot difference value corresponding to the pilot reference
value are obtained. Subsequently, the data are obtained using the pilot
reference value and the pilot difference value. And, the method may
further include a step of decoding at least one of the pilot difference
value and the pilot reference value. In this case, the PBC applied data
are parameters. And, the method may further include the step of
reconstructing an audio signal using the obtained parameters.

[0141]An apparatus for processing a signal according to one embodiment of
the present invention includes a pilot reference value corresponding to a
plurality of data and a pilot difference value corresponding to the pilot
reference value and a data obtaining part obtaining the data using the
pilot reference value and the pilot difference value. In this case, the
value obtaining part and the data obtaining part are included in the
aforesaid data coding part 91 or 92.

[0142]A method of processing a signal according to another embodiment of
the present invention includes the steps of generating a pilot difference
value using a pilot reference value corresponding to a plurality of data
and the data and outputting the generated pilot difference value.

[0143]An apparatus for processing a signal according to another embodiment
of the present invention includes a value generating part generating a
pilot difference value using a pilot reference value corresponding to a
plurality of data and the data and an output part outputting the
generated pilot difference value.

[0144]A method of processing a signal according to a further embodiment of
the present invention includes the steps of obtaining a pilot reference
value corresponding to a plurality of gains and a pilot difference value
corresponding to the pilot reference value and obtaining the gain using
the pilot reference value and the pilot difference value. And, the method
may further include the step of decoding at least one of the pilot
difference value and the pilot reference value. Moreover, the method may
further include the step of reconstructing an audio signal using the
obtained gain.

[0145]In this case, the pilot reference value may be an average of a
plurality of the gains, an averaged intermediate value of a plurality of
the gains, a most frequently used value of a plurality of the gains, a
value set to a default or one value extracted from a table. And, the
method may further include the step of selecting the gain having highest
encoding efficiency as a final pilot reference value after the pilot
reference value has been set to each of a plurality of the gains.

[0146]An apparatus for processing a signal according to a further
embodiment of the present invention includes a value obtaining part
obtaining a pilot reference value corresponding to a plurality of gains
and a pilot difference value corresponding to the pilot reference value
and a gain obtaining part obtaining the gain using the pilot reference
value and the pilot difference value.

[0147]A method of processing a signal according to another further
embodiment of the present invention includes the steps of generating a
pilot difference value using a pilot reference value corresponding to a
plurality of gains and the gains and outputting the generated pilot
difference value.

[0148]And, an apparatus for processing a signal according to another
further embodiment of the present invention includes a value calculating
part generating a pilot difference value using a pilot reference value
corresponding to a plurality of gains and the gains and an outputting
part outputting the generated pilot difference value.

[0149]3. DIFF (Differential Coding)

[0150]DIFF coding is a coding scheme that uses relations between a
plurality of data existing within a discriminated data group, which may
be called `differential coding`. In this case, a data group, which is a
unit in applying the DIFF, means a final group to which a specific
grouping scheme is applied by the aforesaid data grouping part 10. In the
present invention, data having a specific meaning as grouped in the above
manner is defined as `parameter` to be explained. And, this is the same
as explained for the PBC.

[0151]In particular, the DIFF coding scheme is a coding scheme that uses
difference values between parameters existing within a same group, and
more particularly, difference values between neighbor parameters.

[0152]Types and detailed application examples of the DIFF coding schemes
are explained in detail with reference to FIGS. 5 to 8 as follows.

[0153]3-1. DIFF Types

[0154]FIG. 5 is a diagram to explain types of DIFF coding according to the
present invention. DIFF coding is discriminated according to a direction
in finding a difference value from a neighbor parameter.

[0155]For instance, DIFF coding types can be classified into DIFF in
frequency direction (hereinafter abbreviated `DIFF_FREQ` or `DF`) and
DIFF in time direction (hereinafter abbreviated `DIFF_TIME` or `DT`).

[0156]Referring to FIG. 5, Group-1 indicates DIFF(DF) calculating a
difference value in a frequency axis, while Group-2 or Group-3 calculates
a difference value in a time axis.

[0157]As can be seen in FIG. 5, the DIFF(DT), which calculates a
difference value in a time axis, is re-discriminated according to a
direction of the time axis to find a difference value.

[0158]For instance, the DIFF(DT) applied to the Group-2 corresponds to a
scheme that finds a difference value between a parameter value at a
current time and a parameter value at a previous time (e.g., Group-1).
This is called backward time DIFF(DT) (hereinafter abbreviated
`DT-BACKWARD`).

[0159]For instance, the DIFF(DT) applied to the Group-3 corresponds to a
scheme that finds a difference value between a parameter value at a
current time and a parameter value at a next time (e.g., Group-4). This
is called forward time DIFF(DT) (hereinafter abbreviated `DT-FORWARD`).

[0160]Hence, as shown in FIG. 5, the Group-1 is a DIFF(DF) coding scheme,
the Group-2 is a DIFF(DT-BACKWARD) coding scheme, and the Group-3 is a
DIFF(DT-FORWARD) coding scheme. Yet, a coding scheme of the Group-4 is
not decided.

[0161]In the present invention, although DIFF in frequency axis is defined
as one coding scheme (e.g., DIFF(DF)) only, definitions can be made by
discriminating it into `DIFF(DF-TOP)` and `DIFF(DF-BOTTOM)` as well.

[0162]3-2. Examples of DIFF Applications

[0163]FIGS. 6 to 8 are diagrams of examples to which DIFF coding scheme is
applied.

[0165]FIG. 7 shows results from calculating difference values of the
Group-1. Since the Group-1 is coded by the DIFF(DF) coding scheme,
difference values are calculated by Formula 2. Formula 2 means that a
difference value from a previous parameter is found on a frequency axis.

[0167]FIG. 8 shows results from calculating difference values of the
Group-2. Since the Group-2 is coded by the DIFF(DF-BACKWARD) coding
scheme, difference values are calculated by Formula 3. Formula 3 means
that a difference value from a previous parameter is found on a time
axis.

[0170]The present invention is characterized in compressing or
reconstructing data by mixing various data coding schemes. So, in coding
a specific group, it is necessary to select one coding scheme from at
least three or more data coding schemes. And, identification information
for the selected coding scheme should be delivered to a decoding part via
bitstream.

[0171]A method of selecting a data coding scheme and a coding method and
apparatus using the same according to the present invention are explained
as follows.

[0172]A method of processing a signal according to one embodiment of the
present invention includes the steps of obtaining data coding
identification information and data-decoding data according to a data
coding scheme indicated by the data coding identification information.

[0173]In this case, the data coding scheme includes a PBC coding scheme at
least. And, the PBC coding scheme decodes the data using a pilot
reference value corresponding to a plurality of data and a pilot
difference value. And, the pilot difference value is generated using the
data and the pilot reference value.

[0174]The data coding scheme further includes a DIFF coding scheme. The
DIFF coding scheme corresponds to one of DIFF-DF scheme and DIFF-DT
scheme. And, the DIFF-DT scheme corresponds to one of forward time
DIFF-DT(FORWARD) scheme and backward time DIFF-DT(BACKWARD).

[0175]The signal processing method further includes the steps of obtaining
entropy coding identification information and entropy-decoding the data
using an entropy coding scheme indicated by the entropy coding
identification information.

[0176]In the data decoding step, the entropy-decoded data is data-decoded
by the data coding scheme.

[0177]And, the signal processing method further includes the step of
decoding an audio signal using the data as parameters.

[0178]An apparatus for processing a signal according to one embodiment of
the present invention includes

[0179]An identification information obtaining part obtaining data coding
identification information and a decoding part data-decoding data
according to a data coding scheme indicated by the data coding
identification information.

[0180]In this case, the data coding scheme includes a PBC coding scheme at
least. And, the PBC coding scheme decodes the data using a pilot
reference value corresponding to a plurality of data and a pilot
difference value. And, the pilot difference value is generated using the
data and the pilot reference value.

[0181]A method of processing a signal according to another embodiment of
the present invention includes the steps of data-encoding data according
to a data coding scheme and generating to transfer data coding
identification information indicating the data coding scheme.

[0182]In this case, the data coding scheme includes a PBC coding scheme at
least. The PBC coding scheme encodes the data using a pilot reference
value corresponding to a plurality of data and a pilot difference value.
And, the pilot difference value is generated using the data and the pilot
reference value.

[0183]An apparatus for processing a signal according to another embodiment
of the present invention includes an encoding part data-encoding data
according to a data coding scheme and an outputting part generating to
transfer data coding identification information indicating the data
coding scheme.

[0184]In this case, the data coding scheme includes a PBC coding scheme at
least. The PBC coding scheme encodes the data using a pilot reference
value corresponding to a plurality of data and a pilot difference value.
And, the pilot difference value is generated using the data and the pilot
reference value.

[0185]A method of selecting a data coding scheme and a method of
transferring coding selection identification information by optimal
transmission efficiency according to the present invention are explained
as follows.

[0187]FIG. 9 is a block diagram to explain a relation in selecting one of
at least three coding schemes according to the present invention.

[0188]Referring to FIG. 9, it is assumed that there exist first to third
data encoding parts 53, 52 and 51, that frequency of use of the first
data encoding part 53 is lowest, and that frequency of use of the third
data encoding part 51 is highest.

[0189]For convenience of explanation, with reference to total `100`, it is
assumed that frequency of use of the first data encoding part 53 is `10`,
that frequency of use of the second data encoding part 52 is `30`, and
that frequency of use of the third data encoding part 51 is `60`. In
particular, for 100 data groups, it can be regarded PCM scheme is applied
10 times, PBC scheme is applied 30 times, and DIFF scheme is applied 60
times.

[0190]On the above assumptions, a number of bits necessary for
identification information to identify three kinds of coding schemes is
calculated in a following manner.

[0191]For example, according to FIG. 9, since 1-bit first information is
used, 100 bits are used as the first information to identify coding
schemes of total 100 groups. Since the third data encoding part 51 having
the highest frequency of use is identified through the 100 bits, the rest
of 1-bit second information is able to discriminate the first data
encoding part 53 and the second data encoding part 52 using 40 bits only.

[0193]FIG. 10 is a block diagram to explain a relation in selecting one of
at least three coding schemes according to a related art.

[0194]Like FIG. 9, for convenience of explanation, with reference to total
`100`, it is assumed that frequency of use of the first data encoding
part 53 is `10`, that frequency of use of the second data encoding part
52 is `30`, and that frequency of use of the third data encoding part 51
is `60`.

[0195]In FIG. 10, a number of bits necessary for identification
information to identify three coding scheme types is calculated in a
following manner.

[0196]First of all, according to FIG. 10, since 1-bit first information is
used, 100 bits are used as the first information to identify coding
schemes of total 100 groups.

[0197]The first data encoding part 53 having the lowest frequency of use
is preferentially identified through the 100 bits. So, the rest of 1-bit
second information needs total 90 bits more to discriminate the second
data encoding part 52 and the third data encoding part 51.

[0199]Comparing the case shown in FIG. 9 and the case shown in FIG. 10, it
can be seen that the data coding selection identification information
shown in FIG. 9 is more advantageous in transmission efficiency.

[0200]Namely, in case that there exist at least three or more data coding
schemes, the present invention is characterized in utilizing different
identification information instead of discriminating two coding scheme
types similar to each other in frequency of use by the same
identification information.

[0201]For instance, in case that the first data encoding part 51 and the
second data encoding part 52, as shown in FIG. 10, are classified as the
same identification information, data transmission bits increase to lower
transmission efficiency.

[0202]In case that there exist at least three data coding types, the
present invention is characterized in discriminating a data coding scheme
having highest frequency of use by first information. So, by second
information, the rest of the two coding schemes having low frequency of
use each are discriminated.

[0203]FIG. 11 and FIG. 12 are flowcharts for the data coding selecting
scheme according to the present invention, respectively.

[0204]In FIG. 11, it is assumed that DIFF coding is a data coding scheme
having highest frequency of use. In FIG. 12, it is assumed that PBC
coding is a data coding scheme having highest frequency of use.

[0205]Referring to FIG. 11, a presence or non-presence of PCM coding
having lowest frequency of use is checked (S10). As mentioned in the
foregoing description, the check is performed by first information for
identification.

[0206]As a result of the check, if it is the PCM coding, it is checked
whether it is PBC coding (S20). This is performed by second information
for identification.

[0207]In case that frequency of use of DIFF coding is 60 times among total
100 times, identification information for a per-group coding type
selection for the same 100 data groups needs total 140 bits of `first
information (100 bits)+second information (40 bits)`.

[0208]Referring to FIG. 12, like FIG. 11, a presence or non-presence of
PCM coding having lowest frequency of use is checked (S30). As mentioned
in the foregoing description, the check is performed by first information
for identification.

[0209]As a result of the check, if it is the PCM coding, it is checked
whether it is DIFF coding (S40). This is performed by second information
for identification.

[0210]In case that frequency of use of DIFF coding is 80 times among total
100 times, identification information for a per-group coding type
selection for the same 100 data groups needs total 120 bits of `first
information (100 bits)+second information (20 bits)`.

[0211]A method of identifying a plurality of data coding schemes and a
signal processing method and apparatus using the same according to the
present invention are explained as follows.

[0212]A method of processing a signal according to one embodiment of the
present invention includes the steps of extracting identification
information indicating a plurality of data coding schemes hierarchically
and decoding data according to the data coding scheme corresponding to
the identification information.

[0213]In this case, the identification information indicating a PBC coding
scheme and a DIFF coding scheme included in a plurality of the data
coding schemes is extracted from different layers.

[0214]In the decoding step, the data are obtained according to the data
coding scheme using a reference value corresponding to a plurality of
data and a difference value generated using the data. In this case, the
reference value is a pilot reference value or a difference reference
value.

[0215]A method of processing a signal according to another embodiment of
the present invention includes the steps of extracting identification
information indicating at least three or more data coding schemes
hierarchically. In this case, the identification information indicating
two coding schemes having high frequency of use of the identification
information is extracted from different layers.

[0216]A method of processing a signal according to a further embodiment of
the present invention includes the steps of extracting identification
information hierarchically according to frequency of use of the
identification information indicating a data coding scheme and decoding
data according to the data decoding scheme corresponding to the
identification information.

[0217]In this case, the identification information is extracted in a
manner of extracting first identification information and second
identification information hierarchically. The first identification
information indicates whether it is a first data coding scheme and the
second identification information indicates whether it is a second data
coding scheme.

[0218]The first identification information indicates whether it is a DIFF
coding scheme. And, the second identification information indicates
whether it is a pilot coding scheme or a PCM grouping scheme.

[0219]The first data coding scheme can be a PCM coding scheme. And, the
second data coding scheme can be a PBC coding scheme or a DIFF coding
scheme.

[0220]The data are parameters, and the signal processing method further
includes the step of reconstructing an audio signal using the parameters.

[0221]An apparatus for processing a signal according to one embodiment of
the present invention includes an identifier extracting part (e.g., `710`
in FIG. 13) hierarchically extracting identification information
discriminating a plurality of data coding schemes and a decoding part
decoding data according to the data coding scheme corresponding to the
identification information.

[0222]A method of processing a signal according to another further
embodiment of the present invention includes the steps of encoding data
according to a data coding scheme and generating identification
information discriminating data coding schemes differing from each other
in frequency of use used in encoding the data.

[0223]In this case, the identification information discriminates a PCM
coding scheme and a PBC coding scheme from each other. In particular, the
identification information discriminates a PCM coding scheme and a DIFF
coding scheme.

[0224]And, an apparatus for processing a signal according to another
further embodiment of the present invention includes an encoding part
encoding data according to a data coding scheme and an identification
information generating part (e.g., `400` in FIG. 11) generating
identification information discriminating data coding schemes differing
from each other in frequency of use used in encoding the data.

[0225]4-2. Inter-Data-Coding Relations

[0226]First of all, there exist mutually independent and/or dependent
relations between PCM, PBC and DIFF of the present invention. For
instance, it is able to freely select one of the three coding types for
each group becoming a target of data coding. So, overall data coding
brings a result of using the three coding scheme types in combination
with each other. Yet, by considering frequency of use of the three coding
scheme types, one of a DIFF coding scheme having optimal frequency of use
and the rest of the two coding schemes (e.g., PCM and PBC) is primarily
selected. Subsequently, one of the PCM and the PBC is secondarily
selected. Yet, as mentioned in the foregoing description, this is to
consider transmission efficiency of identification information but is not
attributed to similarity of substantial coding schemes.

[0227]In aspect of similarity of coding schemes, the PBC and DIFF are
similar to each other in calculating a difference value. So, coding
processes of the PBC and the DIFF are considerably overlapped with each
other. In particular, a step of reconstructing an original parameter from
a difference value in decoding is defined as `delta decoding` and can be
designed to be handled in the same step.

[0228]In the course of executing PBC or DIFF coding, there may exist a
parameter deviating from its range. In this case, it is necessary to code
and transfer the corresponding parameter by separate PCM.

[0229][Grouping]

[0230]1. Concept of Grouping

[0231]The present invention proposes `grouping` that handles data by
binding prescribed data together for efficiency in coding. In particular,
in case of PBC coding, since a pilot reference value is selected by a
group unit, a grouping process needs to be completed as a step prior to
executing the PBC coding. The grouping is applied to DIFF coding in the
same manner. And, some schemes of the grouping according to the present
invention are applicable to entropy coding as well, which will be
explained in a corresponding description part later.

[0232]Grouping types of the present invention can be classified into
`external grouping` and `internal grouping` with reference to an
executing method of grouping.

[0233]Alternatively, grouping types of the present invention can be
classified into `domain grouping`, `data grouping` and `channel grouping`
with reference to a grouping target.

[0234]Alternatively, grouping types of the present invention can be
classified into `first grouping`, `second grouping` and `third grouping`
with reference to a grouping execution sequence.

[0235]Alternatively, grouping types of the present invention can be
classified into `single grouping` and `multiple grouping` with reference
to a grouping execution count.

[0236]Yet, the above grouping classifications are made for convenience in
transferring the concept of the present invention, which does not put
limitation on its terminologies of use.

[0237]The grouping according to the present invention is completed in a
manner that various grouping schemes are overlapped with each other in
use or used in combination with each other.

[0238]In the following description, the groping according to the present
invention is explained by being discriminated into internal grouping and
external grouping. Subsequently, multiple grouping, in which various
grouping types coexist, will be explained. And, concepts of domain
grouping and data grouping will be explained.

[0239]2. Internal Grouping

[0240]Internal grouping means that execution of grouping is internally
carried out. If internal grouping is carried out in general, a previous
group is internally re-grouped to generate a new group or divided groups.

[0241]FIG. 13 is a diagram to explaining internal grouping according to
the present invention.

[0242]Referring to FIG. 13, internal grouping according to the present
invention is carried out by frequency domain unit (hereinafter named
`band`), for example. So, an internal grouping scheme may correspond to a
sort of domain grouping occasionally.

[0243]If sampling data passes through a specific filter, e.g., QMF
(quadrature mirror filter), a plurality of sub-bands are generated. In
the sub-band mode, first frequency grouping is performed to generate
first group bands that can be called parameter bands. The first frequency
groping is able to generate parameter bands by binding sub-bands together
irregularly. So, it is able to configure sizes of the parameter bands
non-equivalently. Yet, according to a coding purpose, it is able to
configure the parameter bands equivalently. And, the step of generating
the sub-bands can be classified as a sort of grouping.

[0244]Subsequently, second frequency grouping is performed on the
generated parameter bands to generate second group bands that may be
called data bands. The second frequency grouping is able to generate data
bands by unifying parameter bands with uniform number.

[0245]According to a purpose of the coding after completion of the
grouping, it is able to execute coding by parameter band unit
corresponding to the first group band or by data band unit corresponding
to the second group band.

[0246]For instance, in applying the aforesaid PBC coding, it is able to
select a pilot reference value (a sort of group reference value) by
taking grouped parameter bands as one group or by taking grouped data
bands as one group. The PBC is carried out using the selected pilot
reference value and detailed operations of the PBC are the same as
explained in the foregoing description.

[0247]For another instance, in applying the aforesaid DIFF coding, a group
reference value is decided by taking grouped parameter bands as one group
and a difference value is then calculated. Alternatively, it is also
possible to decide a group reference value by taking grouped data bands
as one group and to calculate a difference value. And, detailed
operations of the DIFF are the same as explained in the foregoing
description.

[0248]If the first and/or frequency grouping is applied to actual coding,
it is necessary to transfer corresponding information, which will be
explained with reference to FIG. 23 later.

[0249]3. External Grouping

[0250]External grouping means a case that execution of grouping is
externally carried out. If external grouping is carried out in general, a
previous group is externally re-grouped to generate a new group or
combined groups.

[0251]FIG. 14 is a diagram to explaining external grouping according to
the present invention.

[0252]Referring to FIG. 14, external grouping according to the present
invention is carried out by time domain unit (hereinafter named
`timeslot`), for example. So, an external grouping scheme may correspond
to a sort of domain grouping occasionally.

[0253]First time grouping is performed on a frame including sampling data
to generate first group timeslots. FIG. 14 exemplarily shows that eight
timeslots are generated. The first time grouping has a meaning of
dividing a frame into timeslots in equal size as well.

[0254]At least one of the timeslots generated by the first time grouping
is selected. FIG. 14 shows a case that timeslots 1, 4, 5, and 8 are
selected. According to a coding scheme, it is able to select the entire
timeslots in the selecting step.

[0255]The selected timeslots 1, 4, 5, and 8 are then rearranged into
timeslots 1, 2, 3 and 4. Yet, according to an object of coding, it is
able to rearrange the selected timeslots 1, 4, 5, and 8 in part. In this
case, since the timeslot(s) excluded from the rearrangement is excluded
from final group formation, it is excluded from the PBC or DIFF coding
targets.

[0256]Second time grouping is performed on the selected timeslots to
configure a group handled together on a final time axis.

[0257]For instance, timeslots 1 and 2 or timeslots 3 and 4 can configure
one group, which is called a timeslot pair. For another instance,
timeslots 1, 2 and 3 can configure one group, which is called a timeslot
triple. And, a single timeslot is able to exist not to configure a group
with another timeslot(s).

[0258]In case that the first and second time groupings are applied to
actual coding, it is necessary to transfer corresponding information,
which will be explained with reference to FIG. 23 later.

[0259]4. Multiple Grouping

[0260]Multiple grouping means a grouping scheme that generates a final
group by mixing the internal grouping, the external grouping and various
kinds of other groupings together. As mentioned in the foregoing
description, the individual groping schemes according to the present
invention can be applied by being overlapped with each other or in
combination with each other. And, the multiple grouping is utilized as a
scheme to raise efficiency of various coding schemes.

[0261]4-1. Mixing Internal Grouping and External Grouping

[0262]FIG. 15 is a diagram to explain multiple grouping according to the
present invention, in which internal grouping and external grouping are
mixed.

[0263]Referring to FIG. 15, final grouped bands 64 are generated after
internal grouping has been completed in frequency domain. And, final
timeslots 61, 62 and 63 are generated after external groping has been
completed in time domain.

[0265]In particular two data sets 61a and 61b or another two data sets 62a
and 62b are able to configure a pair by external grouping. The pair of
the data sets is called `data pair`.

[0266]After completion of the multiple grouping, PBC or DIFF coding
application is executed.

[0267]For instance, in case of executing the PBC coding, a pilot reference
value P1, P2 or P3 is selected for the finally completed data pair 61 or
62 or each data set 63 not configuring the data pair. The PBC coding is
then executed using the selected pilot reference values.

[0268]For instance, in case of executing the DIFF coding, a DIFF coding
type is decided for each of the data sets 61a, 61b, 62a, 62b and 63. As
mentioned in the foregoing description, a DIFF direction should be
decided for each of the data sets and is decided as one of `DIFF-DF` and
`DIFF-DT`. A process for executing the DIFF coding according to the
decided DIFF coding scheme is the same as mentioned in the foregoing
description.

[0269]In order to configure a data pair by executing external grouping in
multiple grouping, equivalent internal grouping should be performed on
each of the data sets configuring the data pair.

[0270]For instance, each of the data sets 61a and 61b configuring a data
pair has the same data band number. And, each of the data sets 62a and
62b configuring a data pair has the same data band number. Yet, there is
no problem in that the data sets belonging to different data pairs, e.g.,
61a and 62a, respectively may differ from each other in the data band
number. This means that different internal grouping can be applied to
each data pair.

[0271]In case of configuring a data pair, it is able to perform first
grouping by internal grouping and second groping by external grouping.

[0272]For instance, a data band number after second grouping corresponds
to a prescribed multiplication of a data band number after first
grouping. This is because each data set configuring a data pair has the
same data band number.

[0273]4-2. Mixing Internal Grouping and Internal Grouping

[0274]FIG. 16 and FIG. 17 are diagrams to explain mixed grouping according
to another embodiments of the present invention, respectively. In
particular, FIG. 16 and FIG. 17 intensively show mixing of internal
groupings. So, it is apparent that external grouping is performed or can
be performed in FIG. 16 or FIG. 17.

[0275]For instance, FIG. 16 shows a case that internal grouping is
performed again on a case that data bands are generated after completion
of the second frequency grouping. In particular, the data bands generated
by the second frequency grouping are divided into low frequency band and
high frequency band. In case of specific coding, it is necessary to
utilize the low frequency band or the high frequency band separately. In
particular, a case of separating the low frequency band and the high
frequency band to utilize is called `dual mode`.

[0276]So, in case of dual mode, data coding is performed by taking the
finally generated low or high frequency band as one group. For instance,
pilot reference values P1 and P2 are generated for low and high frequency
bands, respectively and PBC coding is then performed within the
corresponding frequency band.

[0277]The dual mode is applicable according to characteristics per
channel. So, this is called `channel grouping`. And, the dual mode is
differently applicable according to a data type as well.

[0278]For instance, FIG. 17 shows a case that internal grouping is
performed again on a case that data bands are generated after completion
of the aforesaid second frequency grouping. Namely, the data bands
generated by the second frequency grouping are divided into low frequency
band and high frequency band. In case of specific coding, the low
frequency band is utilized only but the high frequency band needs to be
discarded. In particular, a case of grouping the low frequency band to
utilize only is called `low frequency channel (LFE) mode`.

[0279]In the low frequency channel (LFE) mode`, data coding is performed
by taking the finally generated low frequency band as one group.

[0280]For instance, a pilot reference value P1 is generated for a low
frequency band and PBC coding is then performed within the corresponding
low frequency band. Yet, it is possible to generate new data bands by
performing internal grouping on a selected low frequency band. This is to
intensively group the low frequency band to represent.

[0281]And, the low frequency channel (LFE) mode is applied according to a
low frequency channel characteristic and can be called `channel
grouping`.

[0282]5. Domain Grouping and Data Grouping

[0283]Grouping can be classified into domain grouping and data grouping
with reference to targets of the grouping.

[0284]The domain grouping means a scheme of grouping units of domains on a
specific domain (e.g., frequency domain or time domain). And, the domain
grouping can be executed through the aforesaid internal grouping and/or
external grouping.

[0285]And, the data grouping means a scheme of grouping data itself. The
data grouping can be executed through the aforesaid internal grouping
and/or external grouping.

[0286]In a special case of data grouping, groping can be performed to be
usable in entropy coding. For instance, the data grouping is used in
entropy coding real data in a finally completed grouping state shown in
FIG. 15. Namely, data are processed in a manner that two data neighboring
to each other in one of frequency direction and time direction are bound
together.

[0287]Yet, in case that the data grouping is carried out in the above
manner, data within a final group are re-grouped in part. So, PBC or DIFF
coding is not applied to the data-grouped group (e.g., two data) only.
Besides, an entropy coding scheme corresponding to the data grouping will
be explained later.

[0288]6. Signal Processing Method Using Grouping

[0289]6-1. Signal Processing Method Using Internal Grouping at Least

[0290]A signal processing method and apparatus using the aforesaid
grouping scheme according to the present invention are explained as
follows.

[0291]A method of processing a signal according to one embodiment of the
present invention includes the steps of obtaining a group reference value
corresponding to a plurality of data included in one group and a
difference value corresponding to the group reference value through first
grouping and internal grouping for the first grouping and obtaining the
data using the group reference value and the difference value.

[0292]The present invention is characterized in that a number of the data
grouped by the first grouping is greater than a number of the data
grouped by the internal grouping. In this case, the group reference value
can be a pilot reference value or a difference reference value.

[0293]The method according to one embodiment of the present invention
further includes the step of decoding at least one of the group reference
value and the difference value. In this case, the pilot reference value
is decided per the group.

[0294]And, numbers of the data included in internal groups through the
internal grouping are set in advance, respectively. In this case, the
numbers of the data included in the internal groups are different from
each other.

[0295]The first grouping and the internal grouping are performed on the
data on a frequency domain. In this case, the frequency domain may
correspond to one of a hybrid domain, a parameter band domain, a data
band domain and a channel domain.

[0296]And, the present invention is characterized in that a first group by
the first grouping includes a plurality of internal groups by the
internal grouping.

[0297]The frequency domain of the present invention is discriminated by a
frequency band. The frequency band becomes sub-bands by the internal
grouping. The sub-bands become parameter bands by the internal grouping.
The parameter bands become data bands by the internal grouping. In this
case, a number of the parameter bands can be limited to maximum 28. And,
the parameter bands are grouped by 2, 5 or 10 into one data band.

[0298]An apparatus for processing a signal according to one embodiment of
the present invention includes a value obtaining part obtaining a group
reference value corresponding to a plurality of data included in one
group and a difference value corresponding to the group reference value
through first grouping and internal grouping for the first grouping and a
data obtaining part obtaining the data using the group reference value
and the difference value.

[0299]A method of processing a signal according to another embodiment of
the present invention includes the steps of generating a difference value
using a group reference value corresponding to a plurality of data
included in one group through first grouping and internal grouping for
the first grouping and the data and transferring the generated difference
value.

[0300]And, an apparatus for processing a signal according to another
embodiment of the present invention includes a value generating part
generating a difference value using a group reference value corresponding
to a plurality of data included in one group through first grouping and
internal grouping for the first grouping and the data and an outputting
part transferring the generated difference value.

[0301]6-2. Signal Processing Method Using Multiple Grouping

[0302]A signal processing method and apparatus using the aforesaid
grouping scheme according to the present invention are explained as
follows.

[0303]A method of processing a signal according to one embodiment of the
present invention includes the steps of obtaining a group reference value
corresponding to a plurality of data included in one group through
grouping and a difference value corresponding to the group reference
value and obtaining the data using the group reference value and the
difference value.

[0304]In this case, the group reference value can be one of a pilot
reference value and a difference reference value.

[0305]And, the grouping may correspond to one of external grouping and
external grouping.

[0306]Moreover, the grouping may correspond to one of domain grouping and
data grouping.

[0307]The data grouping is performed on a domain group. And, a time domain
included in the domain grouping includes at least one of a timeslot
domain, a parameter set domain and a data set domain.

[0308]A frequency domain included in the domain grouping may include at
least one of a sample domain, a sub-band domain, a hybrid domain, a
parameter band domain, a data band domain and a channel domain.

[0309]One difference reference value will be set from a plurality of the
data included in the group. And, at least one of a grouping count, a
grouping range and a presence or non-presence of the grouping is decided.

[0310]An apparatus for processing a signal according to one embodiment of
the present invention includes a value obtaining part obtaining a group
reference value corresponding to a plurality of data included in one
group through grouping and a difference value corresponding to the group
reference value and a data obtaining part obtaining the data using the
group reference value and the difference value.

[0311]A method of processing a signal according to another embodiment of
the present invention includes the steps of generating a difference value
using a group reference value corresponding to a plurality of data
included in one group through grouping and the data and transferring the
generated difference value.

[0312]An apparatus for processing a signal according to another embodiment
of the present invention includes a value generating part generating a
difference value using a group reference value corresponding to a
plurality of data included in one group through grouping and the data and
an outputting part transferring the generated difference value.

[0313]A method of processing a signal according to another embodiment of
the present invention includes the steps of obtaining a group reference
value corresponding to a plurality of data included in one group through
grouping including first grouping and second grouping and a first
difference value corresponding to the group reference value and obtaining
the data using the group reference value and the first difference value.

[0314]In this case, the group reference value may include a pilot
reference value or a difference reference value.

[0315]The method further includes the step of decoding at least one of the
group reference value and the first difference value. And, the first
pilot reference value is decided per the group.

[0316]The method further includes the steps of obtaining a second pilot
reference value corresponding to a plurality of the first pilot reference
values and a second difference value corresponding to the second pilot
reference value and obtaining the first pilot reference value using the
second pilot reference value and the second difference value.

[0317]In this case, the second grouping may include external or internal
grouping for the first grouping.

[0318]The grouping is performed on the data on at least one of a time
domain and a frequency domain. In particular, the grouping is a domain
grouping that groups at least one of the time domain and the frequency
domain.

[0319]The time domain may include a timeslot domain, a parameter set
domain or a data set domain.

[0320]The frequency domain may include a sample domain, a sub-band domain,
a hybrid domain, a parameter band domain, a data band domain or a channel
domain. And, the grouped data is an index or parameter.

[0321]The first difference value is entropy-decoded using an entropy table
indicated by the index included in one group through the first grouping.
And, the data is obtained using the group reference value and the
entropy-decoded first difference value.

[0322]The first difference value and the group reference value are
entropy-decoded using an entropy table indicated by the index included in
one group through the first grouping. And, the data is obtained using the
entropy-decoded group reference value and the entropy-decoded first
difference value.

[0323]An apparatus for processing a signal according to another embodiment
of the present invention includes a value obtaining part obtaining a
group reference value corresponding to a plurality of data included in
one group through grouping including first grouping and second grouping
and a difference value corresponding to the group reference value and a
data obtaining part obtaining the data using the group reference value
and the difference value.

[0324]A method of processing a signal according to another embodiment of
the present invention includes the steps of generating a difference value
using a group reference value corresponding to a plurality of data
included in one group through grouping including first grouping and
second grouping and the data and transferring the generated difference
value.

[0325]An apparatus for processing a signal according to another embodiment
of the present invention includes a value generating part generating a
difference value using a group reference value corresponding to a
plurality of data included in one group through grouping including first
grouping and second grouping and the data and an outputting part
transferring the generated difference value.

[0326]A method of processing a signal according to another embodiment of
the present invention includes the steps of obtaining a group reference
value corresponding to a plurality of data included in one group through
first grouping and external grouping for the first grouping and a
difference value corresponding to the group reference value and obtaining
the data using the group reference value and the difference value.

[0327]In this case, a first data number corresponding to a number of the
data grouped by the first grouping is smaller than a second data number
corresponding to a number of the data grouped by the external grouping.
And, a multiplication relation exists between the first data number and
the second data number.

[0328]The group reference value may include a pilot reference value or a
difference reference value.

[0329]The method further includes the step of decoding at least one of the
group reference value and the difference value.

[0330]The pilot reference value is decoded per the group.

[0331]The grouping is performed on the data on at least one of a time
domain and a frequency domain. The time domain may include a timeslot
domain, a parameter set domain or a data set domain. And, the frequency
domain may include a sample domain, a sub-band domain, a hybrid domain, a
parameter band domain, a data band domain or a channel domain.

[0332]The method further includes the step of reconstructing the audio
signal using the obtained data as parameters. And, the external grouping
may include paired parameters.

[0333]An apparatus for processing a signal according to another embodiment
of the present invention includes a value obtaining part obtaining a
group reference value corresponding to a plurality of data included in
one group through first grouping and external grouping for the first
grouping and a difference value corresponding to the group reference
value and a data obtaining part obtaining the data using the group
reference value and the difference value.

[0334]A method of processing a signal according to a further embodiment of
the present invention includes the steps of generating a difference value
using a group reference value corresponding to a plurality of data
included in one group through first grouping and external grouping for
the first grouping and the data and transferring the generated difference
value.

[0335]And, an apparatus for processing a signal according to a further
embodiment of the present invention includes a value generating part
generating a difference value using a group reference value corresponding
to a plurality of data included in one group through first grouping and
external grouping for the first grouping and the data and an outputting
part transferring the generated difference value.

[0336]6.3. Signal Processing Method Using Data Grouping at Least

[0337]A signal processing method and apparatus using the aforesaid
grouping scheme according to the present invention are explained as
follows.

[0338]A method of processing a signal according to one embodiment of the
present invention includes the steps of obtaining a group reference value
corresponding to a plurality of data included in one group through data
grouping and internal grouping for the data grouping and a difference
value corresponding to the group reference value and obtaining the data
using the group reference value and the difference value.

[0339]In this case, a number of the data included in the internal grouping
is smaller than a number of the data included in the data grouping. And,
the data correspond to parameters.

[0340]The internal grouping is performed on a plurality of the
data-grouped data entirely. In this case, the internal grouping can be
performed per a parameter band.

[0341]The internal grouping can be performed on a plurality of the
data-grouped data partially. In this case, the internal grouping can be
performed per a channel of each of a plurality of the data-grouped data.

[0342]The group reference value can include a pilot reference value or a
difference reference value.

[0343]The method may further include the step of decoding at least one of
the group reference value and the difference value. In this case, the
pilot reference value is decided per the group.

[0344]The data grouping and the internal grouping are performed on the
data on a frequency domain.

[0345]The frequency domain may include one of a sample domain, a sub-band
domain, a hybrid domain, a parameter band domain, a data band domain and
a channel domain. In obtaining the data, grouping information for at
least one of the data grouping and the internal grouping is used.

[0346]The grouping information includes at least one of a position of each
group, a number of each group, a presence or non-presence of applying the
group reference value per a group, a number of the group reference
values, a codec scheme of the group reference value and a presence or
non-presence of obtaining the group reference value.

[0347]An apparatus for processing a signal according to one embodiment of
the present invention includes a value obtaining part obtaining a group
reference value corresponding to a plurality of data included in one
group through data grouping and internal grouping for the data grouping
and a difference value corresponding to the group reference value and a
data obtaining part obtaining the data using the group reference value
and the difference value.

[0348]A method of processing a signal according to another embodiment of
the present invention includes the steps of generating a difference value
using a group reference value corresponding to a plurality of data
included in one group through data grouping and internal grouping for the
data grouping and the data and transferring the generated difference
value.

[0349]And, an apparatus for processing a signal according to another
embodiment of the present invention includes a value generating part
generating a difference value using a group reference value corresponding
to a plurality of data included in one group through data grouping and
internal grouping for the data grouping and the data and an outputting
part transferring the generated difference value.

[Entropy Coding]

[0350]1. Concept of Entropy Coding

[0351]Entropy coding according to the present invention means a process
for performing variable length coding on a result of the data coding.

[0352]In general, entropy coding processes occurrence probability of
specific data in a statistical way. For instance, transmission efficiency
is raised overall in a manner of allocating less bits to data having high
frequency of occurrence in probability and more bits to data having low
frequency of occurrence in probability.

[0353]And, the present invention intends to propose an efficient entropy
coding method, which is different from the general entropy coding,
interconnected with the PBC coding and the DIFF coding.

[0354]1-1. Entropy Table

[0355]First of all, a predetermined entropy table is necessary for entropy
coding. The entropy table is defined as a codebook. And, an encoding part
and a decoding part use the same table.

[0358]Entropy coding of the present invention is classified into two
types. One is to derive one index (index 1) through one entropy table,
and the other is to derive two consecutive indexes (index 1 and index 2)
through one entropy table. The former is named `1D (one-dimensional)
entropy coding` and the latter is named `2D (two-dimensional) entropy
coding`.

[0359]FIG. 18 is an exemplary diagram of 1D and 2D entropy table according
to the present invention. Referring to FIG. 18, an entropy table of the
present invention basically includes an index field, a length field and a
codeword field.

[0360]For instance, if specific data (e.g., pilot reference value,
difference value, etc.) is calculated through the aforesaid data coding,
the corresponding data (corresponding to `index`) has a codeword
designated through the entropy table. The codeword turns into a bitstream
and is then transferred to a decoding part.

[0361]An entropy decoding part having received the codeword decides the
entropy table having used for the corresponding data and then derives an
index value using the corresponding codeword and a bit length configuring
the codeword within the decided table. In this case, the present
invention represents a codeword as hexadecimal.

[0362]A positive sign (+) or a negative sign (-) of an index value derived
by 1D or 2D entropy coding is omitted. So, it is necessary to assign the
sign after completion of the 1D or 2D entropy coding.

[0363]In the present invention, the sign is assigned differently according
to 1D or 2D.

[0364]For instance, in case of 1D entropy coding, if a corresponding index
is not `0`, a separate 1-bit sign bit (e.g., `bsSign`) is allocated and
transferred.

[0365]In case of 2D entropy coding, since two indexes are consecutively
extracted, whether to allocate a sign bit is decided in a manner of
programming a relation between the two extracted indexes. In this case,
the program uses an added value of the two extracted indexes, a
difference value between the two extracted indexes and a maximum absolute
value (lav) within a corresponding entropy table. This is able to reduce
a number of transmission bits, compared to a case that a sign bit is
allocated to each index in case of a simple 2D.

[0366]The 1D entropy table, in which indexes are derived one by one, is
usable for all data coding results. Yet, the 2D entropy table, in which
two indexes are derived each, has a restricted use for a specific case.

[0367]For instance, if data coding is not a pair through the aforesaid
grouping process, the 2D entropy table has a restricted use in part. And,
a use of the 2D entropy table is restricted on a pilot reference value
calculated as a result of PBC coding.

[0368]Therefore, as mentioned in the foregoing description, entropy coding
of the present invention is characterized in utilizing a most efficient
entropy coding scheme in a manner that entropy coding is interconnected
with the result of data coding. This is explained in detail as follows.

[0369]1-3. 2D Method (Time Pairing/Frequency Paring)

[0370]FIG. 19 is an exemplary diagram of two methods for 2D entropy coding
according to the present invention. 2D entropy coding is a process for
deriving two indexes neighboring to each other. So, the 2D entropy coding
can be discriminated according to a direction of the two consecutive
indexes.

[0371]For instance, a case that two indexes are neighbor to each other in
frequency direction is called `2D-Freqeuncy Pairing (hereinafter
abbreviated 2D-FP)`. And, a case that two indexes are neighbor to each
other in time direction is called `2D-Time Pairing (hereinafter
abbreviated 2D-TP)`.

[0372]Referring to FIG. 19, the 2D-FP and the 2D-TP are able to configure
separate index tables, respectively. An encoder has to decide a most
efficient entropy coding scheme according to a result of data decoding.

[0373]A method of deciding entropy coding interconnected with data coding
efficiently is explained in the following description.

[0374]1-4. Entropy Coding Signal Processing Method

[0375]A method of processing a signal using entropy coding according to
the present invention is explained as follows.

[0376]In a method of processing a signal according to one embodiment of
the present invention, a reference value corresponding to a plurality of
data and a difference value corresponding to the reference value are
obtained. Subsequently, the difference value is entropy-decoded. The data
is then obtained using the reference value and the entropy-decoded
difference value.

[0377]The method further includes the step of entropy-decoding the
reference value. And, the method may further include the step of
obtaining the data using the entropy-decoded reference value and the
entropy-decoded difference value.

[0378]The method can further include the step of obtaining entropy coding
identification information. And, the entropy coding is performed
according to an entropy coding scheme indicated by the entropy coding
identification information.

[0379]In this case, the entropy coding scheme is one of a 1D coding scheme
and a multi-dimensional coding scheme (e.g., 2D coding scheme). And, the
multi-dimensional coding scheme is one of a frequency pair (FP) coding
scheme and a time pair (TP) coding scheme.

[0380]The reference value may include one of a pilot reference value and a
difference reference value.

[0381]And, the signal processing method can further include the step of
reconstructing the audio signal using the data as parameters.

[0382]An apparatus for processing a signal according to one embodiment of
the present invention includes a value obtaining part obtaining a
reference value corresponding to a plurality of data and a difference
value corresponding to the reference value, an entropy decoding part
entropy-decoding the difference value, and a data obtaining part
obtaining the data using the reference value and the entropy-decoded
difference value.

[0383]In this case, the value obtaining part is included in the aforesaid
bitstream demultiplexing part 60 and the data obtaining part is included
within the aforesaid data decoding part 91 or 92.

[0384]A method of processing a signal according to another embodiment of
the present invention includes the steps of generating a difference value
using a reference value corresponding to a plurality of data and the
data, entropy-encoding the generated difference value, and outputting the
entropy-encoded difference value.

[0385]In this case, the reference value is entropy-encoded. The
entropy-encoded reference value is transferred.

[0386]The method further includes the step of generating an entropy coding
scheme used for the entropy encoding. And, the generated entropy coding
scheme is transferred.

[0387]An apparatus for processing a signal according to another embodiment
of the present invention includes a value generating part generating a
difference value using a reference value corresponding to a plurality of
data and the data, an entropy encoding part entropy-encoding the
generated difference value, and an outputting part outputting the
entropy-encoded difference value.

[0388]In this case, the value generating part is included within the
aforesaid data encoding part 31 or 32. And, the outputting part is
included within the aforesaid bitstream multiplexing part 50.

[0389]A method of processing a signal according to another embodiment of
the present invention includes the steps of obtaining data corresponding
to a plurality of data coding schemes, deciding an entropy table for at
least one of a pilot reference value and a pilot difference value
included in the data using an entropy table identifier unique to the data
coding scheme, and entropy-decoding at least one of the pilot reference
value and the pilot difference value using the entropy table.

[0390]In this case, the entropy table identifier is unique to one of a
pilot coding scheme, a frequency differential coding scheme and a time
differential coding scheme.

[0391]And, the entropy table identifier is unique to each of the pilot
reference value and the pilot difference value.

[0392]The entropy table is unique to the entropy table identifier and
includes one of a pilot table, a frequency differential table and a time
differential table.

[0393]Alternatively, the entropy table is not unique to the entropy table
identifier and one of a frequency differential table and a time
differential table can be shared.

[0394]The entropy table corresponding to the pilot reference value is able
to use a frequency differential table. In this case, the pilot reference
value is entropy-decoded by the 1D entropy coding scheme.

[0396]And, the present method is able to reconstruct the audio signal
using the data as parameters.

[0397]An apparatus for processing a signal according to another embodiment
of the present invention includes a value obtaining part obtaining a
pilot reference value corresponding to a plurality of data and a pilot
difference value corresponding to the pilot reference value and an
entropy decoding part entropy-decoding the pilot difference value. And,
the apparatus includes a data obtaining part obtaining the data using the
pilot reference value and the entropy-decoded pilot difference value.

[0398]A method of processing a signal according to a further embodiment of
the present invention includes the steps of generating a plot difference
value using a pilot reference value corresponding to a plurality of data
and the data, entropy-encoding the generated pilot difference value, and
transferring the entropy-encoded pilot difference value.

[0399]In this case, a table used for the entropy encoding may include a
pilot dedicated table.

[0400]The method further includes the step of entropy-encoding the pilot
reference value. And, the entropy-encoded pilot reference value is
transferred.

[0401]The method further includes the step of generating an entropy coding
scheme used for the entropy encoding. And, the generated entropy coding
scheme is transferred.

[0402]An apparatus for processing a signal according to a further
embodiment of the present invention includes a value generating part
generating a plot difference value using a pilot reference value
corresponding to a plurality of data and the data, an entropy encoding
part entropy-encoding the generated pilot difference value, and an
outputting part transferring the entropy-encoded pilot difference value.

[0403]2. Relation to Data Coding

[0404]As mentioned in the foregoing description, the present invention has
proposed three kinds of data coding schemes. Yet, entropy coding is not
performed on the data according to the PCM scheme. Relations between PBC
coding and entropy coding and relations between DIF coding and entropy
coding are separately explained in the following description.

[0405]2-1. PBC Coding and Entropy Coding

[0406]FIG. 20 is a diagram of an entropy coding scheme for PBC coding
result according to the present invention.

[0407]As mentioned in the foregoing description, after completion of PBC
coding, one pilot reference value and a plurality of differences values
are calculated. And, all of the pilot reference value and the difference
values become targets of entropy coding.

[0408]For instance, according to the aforesaid grouping method, a group to
which PBC coding will be applied is decided. In FIG. 20, for convenience
of explanation, a case of a pair on a time axis and a case of non-pair on
a time axis are taken as examples. Entropy coding after completion of PBC
coding is explained as follows.

[0409]First of all, a case 83 that PBC coding is performed on non-pairs is
explained. 1D entropy coding is performed on one pilot reference value
becoming an entropy coding target, and 1D entropy coding or 2D-FP entropy
coding can be performed on the rest difference values.

[0410]In particular, since one group exists for one data set on a time
axis in case of non-pair, it is unable to perform 2D-TP entropy coding.
Even if 2D-FP is executed, 1D entropy coding should be performed on a
parameter value within a last band 81a failing to configure a pair after
pairs of indexes have been derived. Once a per-data entropy coding scheme
is decided, a codeword is generated using a corresponding entropy table.

[0411]Since the present invention relates to a case that one pilot
reference value is generated for one group for example, 1D entropy coding
should be performed. Yet, in another embodiment of the present invention,
if at least two pilot reference values are generated from one group, it
may be possible to perform 2D entropy coding on consecutive pilot
reference values.

[0412]Secondly, a case 84 of performing PBC coding on pairs is explained
as follows.

[0413]1D entropy coding is performed on one pilot reference value becoming
an entropy coding target, and 1D entropy coding, 2D-FP entropy coding or
2D-TP entropy coding can be performed on the rest difference values.

[0414]In particular, since one group exists for two data sets neighbor to
each other on a time axis in case of pairs, it is able to perform 2D-TP
entropy coding. Even if 2D-FP is executed, 1D entropy coding should be
performed on a parameter value within a last band 81b or 81c failing to
configure a pair after pairs of indexes have been derived. Yet, as can be
confirmed in FIG. 20, in case of applying 2D-TP entropy coding, a last
band failing to configure a pair does not exist.

[0415]2-2. DIFF Coding and Entropy Coding

[0416]FIG. 21 is a diagram of entropy coding scheme for DIFF coding result
according to the present invention.

[0417]As mentioned in the foregoing description, after completion of DIFF
coding, one pilot reference value and a plurality of differences values
are calculated. And, all of the pilot reference value and the difference
values become targets of entropy coding. Yet, in case of DIFF-DT, a
reference value may not exist.

[0418]For instance, according to the aforesaid grouping method, a group to
which DIFF coding will be applied is decided. In FIG. 21, for convenience
of explanation, a case of a pair on a time axis and a case of non-pair on
a time axis are taken as examples. And, FIG. 21 shows a case that a data
set as a unit of data coding is discriminated into DIFF-DT in time axis
direction and DIFF-DF in frequency axis direction according to DIFF
coding direction.

[0419]Entropy coding after completion of DIFF coding is explained as
follows.

[0420]First of all, a case that DIFF coding is performed on non-pairs is
explained. In case of non-pairs, one data set exists on a time axis. And,
the data set may become DIFF-DF or DIFF-DT according to DIF coding
direction.

[0421]For instance, if one data set of non-pair is DIFF-DF (85), a
reference value becomes a parameter value within a first band 82a. 1D
entropy coding is performed on the reference value and 1D entropy coding
or 2D-FP entropy coding can be performed on the rest difference values.

[0422]Namely, in case of DIFF-DF as well as non-pair, one group for one
data set exists on a time axis. So, it is unable to perform 2D-TP entropy
coding. Even if 2D-FP is executed, after pairs of indexes have been
derived, 1D entropy coding should be performed on a parameter value
within a last parameter band 83a failing to configure a pair. Once a
coding scheme is decoded for each data, a codeword is generated using a
corresponding entropy table.

[0423]For instance, in case that one data set of non-pair is DIFF-DT (86),
since a reference value does not exist within the corresponding data set,
`first band` processing is not performed. So, 1D entropy coding or 2D-FP
entropy coding can be performed on the difference values.

[0424]In case of DIFF-DT as well as non-pair, a data set to find a
difference value may be a neighbor data set failing to configure a data
pair or a data set within another audio frame.

[0425]Namely, in case of DIFF-DT as well as non-pair (86), there exists
one group for one data set on a time axis. So, it is unable to perform
2D-TP entropy coding. Even if 2D-FP is executed, after pairs of indexes
have been derived, 1D entropy coding should be performed on a parameter
value within a last parameter band failing to configure a pair. Yet, FIG.
21 just shows a case that a last band failing to configure a pair does
not exist, for example.

[0426]Once a coding scheme is decoded for each data, a codeword is
generated using a corresponding entropy table.

[0427]Secondly, a case that DIFF coding is performed on pairs is
explained. In case that data coding is performed on pairs, two data sets
configure one group on a time axis. And, each of the data sets within the
group can become DIFF-DF or DIFF-DT according to DIFF coding direction.
So, it can be classified into a case that both two data sets configuring
a pair are DIFF-DF (87), a case that both two data sets configuring a
pair are DIFF-DT, and a case that two data sets configuring a pair have
different coding directions (e.g., DIFF-DF/DT or DIFF-DT/DF),
respectively (88).

[0428]For instance, in case that both two data sets configuring a pair are
DIFF-DF (i.e., DIFF-DF/DF) (87), if each of the data sets is non-paired
and DIFF-DF, if all available entropy coding schemes are executable.

[0429]For instance, each reference value within the corresponding data set
becomes a parameter value within a first band 82b or 82c and 1D entropy
coding is performed on the reference value. And, 1D entropy coding or
2D-FP entropy coding can be performed on the rest difference values.

[0430]Even if 2D-FP is performed within a corresponding data set, after
pairs of indexes have been derived, 1D entropy coding should be performed
on a parameter value within a last band 83b or 83c failing to configure a
pair. Since two data sets configure a pair, 2D-TP entropy coding can be
performed. In this case, 2D-TP entropy coding is sequentially performed
on bands ranging from a next band excluding the first band 82b or 82c
within the corresponding data set to a last band.

[0431]If the 2D-TP entropy coding is performed, a last band failing to
configure a pair is not generated.

[0432]Once the entropy coding scheme per data is decided, a codeword is
generated using a corresponding entropy table.

[0433]For instance, in case that both of the two data sets configuring the
pair are DIFF-DT (i.e., DIFF-DT/DT) (89), since a reference value does
not exist within a corresponding data set, first band processing is not
performed. And, 1D entropy coding or 2D-Fp entropy coding can be
performed on all the difference values within each of the data sets.

[0434]Even if 2D-FP is performed within a corresponding data set, after
pairs of indexes have been derived, 1D entropy coding should be performed
on a parameter value within a last band failing to configure a pair. Yet,
FIG. 21 shows an example that a last band failing to configure a pair
does not exist.

[0435]Since two data sets configure a pair, 2D-TP entropy coding is
executable. In this case, 2D-TP entropy coding is sequentially performed
on bands ranging from a first band to a last band within the
corresponding data set.

[0436]If the 2D-TP entropy coding is performed, a last band failing to
configure a pair is not generated.

[0437]Once the entropy coding scheme per data is decided, a codeword is
generated using a corresponding entropy table.

[0438]For instance, there may exist a case that two data sets configuring
a pair have different coding directions, respectively (i.e., DIFF-DF/DT
or DIFF-DT/DF) (88). FIG. 21 shows an example of DIFF-DF/DT. In this
case, all entropy coding schemes applicable according to corresponding
coding types can be basically performed on each o the data sets.

[0439]For instance, in a data set of DIFF-DF among two data sets
configuring a pair, 1D entropy coding is performed on a parameter value
within a first band 82d with a reference value within the corresponding
data set (DIFF-DF). And, 1D entropy coding or 2D-FP entropy coding can be
performed on the rest difference values.

[0440]Even if 2D-FP is performed within a corresponding data set
(DIFF-DF), after pairs of indexes have been derived, 1D entropy coding
should be performed on a parameter value within a last band 83d failing
to configure a pair.

[0441]For instance, in a data set of DIFF-DT among two data sets
configuring a pair, since a reference value does not exist, first band
processing is not performed. And, 1D entropy coding or 2D-FP entropy
coding can be performed on all difference values within the corresponding
data set (DIFF-DT).

[0442]Even if 2D-FP is performed within a corresponding data set
(DIFF-DT), after pairs of indexes have been derived, 1D entropy coding
should be performed on a parameter value within a last band failing to
configure a pair. Yet, FIG. 21 shows an example that a last band failing
to configure a pair does not exist.

[0443]Since the two data sets configuring the pair have the coding
directions different from each other, respectively, 2D-TP entropy coding
is executable. In this case, 2D-TP entropy coding is sequentially
performed on bands ranging from a next band excluding a first band
including the first band 82d to a last band.

[0444]If the 2D-TP entropy coding is performed, a last band failing to
configure a pair is not generated.

[0445]Once the entropy coding scheme per data is decided, a codeword is
generated using a corresponding entropy table.

[0446]2-3. Entropy Coding and Grouping

[0447]As mentioned in the foregoing description, in case of 2D-FP or 2D-TP
entropy coding, two indexes are extracted using one codeword. So, this
means that a grouping scheme is performed for entropy coding. And, this
can be named `time grouping` or `frequency grouping`.

[0448]For instance, an encoding part groups two indexes extracted in a
data coding step in frequency or time direction.

[0449]Subsequently, the encoding part selects one codeword representing
the two grouped indexes using an entropy table and then transfers the
selected codeword by having it included in a bitstream.

[0450]A decoding part receives one codeword resulting from grouping the
two indexes included in the bitstream and the extracts two index values
using the applied entropy table.

[0452]The features of the signal processing method according to the
present invention by the relation between PBC coding and entropy coding
and the relation between DIFF coding and entropy coding are explained as
follows.

[0453]A method of processing a signal according to one embodiment of the
present invention includes the steps of obtaining difference information,
entropy-decoding the difference information according to an entropy
coding scheme including time grouping and frequency grouping, and
data-decoding the difference information according to a data decoding
scheme including a pilot difference, a time difference and a frequency
difference. And, detailed relations between data coding and entropy
coding are the same as explained in the foregoing description.

[0454]A method of processing a signal according to another embodiment of
the present invention includes the steps of obtaining a digital signal,
entropy-decoding the digital signal according to an entropy coding
scheme, and data-decoding the entropy-decoded digital signal according to
one of a plurality of data coding schemes including a pilot coding scheme
at least. In this case, the entropy coding scheme can be decided
according to the data coding scheme.

[0455]An apparatus for processing a signal according to another embodiment
of the present invention includes a signal obtaining part obtaining a
digital signal, an entropy decoding part entropy-decoding the digital
signal according to an entropy coding scheme, and a data decoding part
data-decoding the entropy-decoded digital signal according to one of a
plurality of data coding schemes including a pilot coding scheme at
least.

[0456]A method of processing a signal according to a further embodiment of
the present invention includes the steps of data-encoding a digital
signal by a data coding scheme, entropy-encoding the data-encoded digital
signal by an entropy coding scheme, and transferring the entropy-encoded
digital signal. In this case, the entropy coding scheme can be decided
according to the data coding scheme.

[0457]And, an apparatus for processing a signal according to a further
embodiment of the present invention includes a data encoding part
data-encoding a digital signal by a data coding scheme and an entropy
encoding part entropy-encoding the data-encoded digital signal by an
entropy coding scheme. And, the apparatus may further include an
outputting part transferring the entropy-encoded digital signal.

[0458]3. Selection for Entropy Table

[0459]An entropy table for entropy coding is automatically decided
according to a data coding scheme and a type of data becoming an entropy
coding target.

[0460]For instance, if a data type is a CLD parameter and if an entropy
coding target is a pilot reference value, 1D entropy table to which a
table name `hcodPilot_CLD` is given is used for entropy coding.

[0461]For instance, if a data type is a CPC parameter, if data coding is
DIFF-DF, and if an entropy coding target is a first band value, 1D
entropy table to which a table name `hcodFirstband_CPC` is given is used
for entropy coding.

[0462]For instance, if a data type is an ICC parameter, if a data coding
scheme is PBC, and if entropy coding is performed by 2D-TP, 2D-PC/TP
entropy table to which a table name `hcod2D_ICC_PC_TP_LL` is given is
used for entropy coding. In this case, `LL` within the 2D table name
indicates a largest absolute value (hereinafter abbreviated `LAV`) within
the table. And, the largest absolute value (LAV) will be explained later.

[0463]For instance, if a data type is an ICC parameter, if a data coding
scheme is DIF-DF, and if entropy coding is performed by 2D-FP, 2D-FP
entropy table to which a table name `hcod2D_ICC_DF_FP_LL` is given is
used for entropy coding.

[0464]Namely, it is very important to decide to perform entropy coding
using which one of a plurality of entropy tables. And, it is preferable
that an entropy table suitable for a characteristic of each data becoming
each entropy target is configured independent.

[0465]Yet, entropy tables for data having attributes similar to each other
can be shared to use. For representative example, if a data type is `ADG`
or `ATD`, it is able to apply the CLD entropy table. And, a `first band`
entropy table can be applied to a pilot reference value of PBC coding.

[0466]A method of selecting an entropy table using the largest absolute
value (LAV) is explained in detail as follows.

[0467]3-1. Largest Absolute Vale (LAV) of Entropy Table

[0468]FIG. 22 is a diagram to explain a method of selecting an entropy
table according to the present invention.

[0469]A plurality of entropy tables are shown in (a) of FIG. 22, and a
table to select the entropy tables is shown in (b) of FIG. 22.

[0470]As mentioned in the foregoing description, there exist a plurality
of entropy tables according to data coding and data types.

[0472]In particular, although it is preferable that a table is configured
by giving a codeword to each index that can occur in corresponding data,
if so, a size of the table considerably increases. And, it is
inconvenient to manage indexes that are unnecessary or barely occur. In
case of a 2D entropy table, those problems bring more inconvenience due
to too many occurrences. To solve those problems, the largest absolute
value (LAV) is used.

[0473]For instance, if a range of an index value for a specific data type
(e.g., CLD) is between `-X˜+X` (X=15), at least one LAV having high
frequency of occurrence in probability is selected within the range and
is configured into a separate table.

[0474]For instance, in configuring a CLD entropy table, it is able to
provide a table of `LAV=3`, a table of `LAV=5`, a table of `LAV=7` or a
table of `LAV=9`.

[0475]For instance, in (a) of FIG. 22, it is able to set the table-1 91a
to the CLD table of `LAV=3`, the table-2 91b to the CLD table of `LAV=5`,
the table-3 91c to the CLD table of `LAV=7`, and the table-4 91d to the
CLD table of `LAV=9`.

[0476]Indexes deviating from the LAV range within the LAV table are
handled by escape entropy tables (e.g., tables n-2˜n-1).

[0478]Likewise, it is able to set the LAV table for another data type
(e.g., ICC, CPC, etc.) in the same manner of the CLD table. Yet, LAV for
each data has a different value because a range per data type varies.

[0479]For instance, in configuring an ICC entropy table, for example, it
is able to provide a table of `LAV=1`, a table of `LAV=3`, a table of
`LAV=5`, and a table of `LAV=7`. In configuring a CPC entropy table, for
example, it is able to provide a table of `LAV=3`, a table of `LAV=6`, a
table of `LAV=9`, and a table of `LAV=12`.

[0480]3-2. Entropy Table for LAV Index

[0481]The present invention employs an LAV index to select an entropy
table using LAV. Namely, LAV value per data type, as shown in (b) of FIG.
22, is discriminated by LAV index.

[0482]In particular, to select an entropy table to be finally used, LAV
index per a corresponding data type is confirmed and LAV corresponding to
the LAV index is then confirmed. The finally confirmed LAV value
corresponds to `LL` in the configuration of the aforesaid entropy table
name.

[0483]For instance, if a data type is a CLD parameter, if a data coding
scheme is DIFF-DF, if entropy coding is performed by 2D-FP, and if
`LAV=3`, an entropy table to which a table name
`hcod2D_CLD_DF_FP--03` is used for entropy coding.

[0484]In confirming the per data type LAV index, the present invention is
characterized in using an entropy table for LAV index separately. This
means that LAV index itself is handled as a target of entropy coding.

[0485]For instance, the table-n in (a) of FIG. 22 is used as an LAV index
entropy table 91e. This is represented as Table 1.

[0487]For instance, since `LAV Index=0` has highest frequency of use, one
bit is allocated to it. And, two bits are allocated to `LAV Index=1`
having second highest frequency of use. Finally, three bits are allocated
to `LAV=2 or 3` having low frequency of use.

[0488]In case that the LAV Index entropy table 91e is not used, 2-bit
identification information should be transferred to discriminate four
kinds of LAV Indexes each time an LAV entropy table is used.

[0489]Yet, if the LAV Index entropy table 91e of the present invention is
used, it is enough to transfer 1-bit codeword for a case of `LAV Index=0`
having at least 60% frequency of use for example. So, the present
invention is able to raise transmission efficiency higher than that of
the related art method.

[0490]In this case, the LAV Index entropy table 91e in Table 1 is applied
to a case of four kinds of LAV Indexes. And, it is apparent that
transmission efficiency can be more enhanced if there are more LAV
Indexes.

[0491]3-3. Signal Processing Method Using Entropy Table Selection

[0492]A signal processing method and apparatus using the aforesaid entropy
table selection are explained as follows.

[0493]A method of processing a signal according to one embodiment of the
present invention includes the steps of obtaining index information,
entropy-decoding the index information, and identifying a content
corresponding to the entropy-decoded index information.

[0494]In this case, the index information is information for indexes
having characteristics of frequency of use with probability.

[0495]As mentioned in the foregoing description, the index information is
entropy-decoded using the index dedicated entropy table 91e.

[0496]The content is classified according to a data type and is used for
data decoding. And, the content may become grouping information.

[0497]The grouping information is information for grouping of a plurality
of data.

[0498]And, an index of the entropy table is a largest absolute value (LAV)
among indexes included in the entropy table.

[0499]Moreover, the entropy table is used in performing 2D entropy
decoding on parameters.

[0500]An apparatus for processing a signal according to one embodiment of
the present invention includes an information obtaining part obtaining
index information, a decoding part entropy-decoding the index
information, and an identifying part identifying a content corresponding
to the entropy-decoded index information.

[0501]A method of processing a signal according to another embodiment of
the present invention includes the steps of generating index information
to identify a content, entropy-encoding the index information, and
transferring the entropy-encoded index information.

[0502]An apparatus for processing a signal according to another embodiment
of the present invention includes an information generating part
generating index information to identify a content, an encoding part
entropy-encoding the index information, and an information outputting
part transferring the entropy-encoded index information.

[0503]A method of processing a signal according to another embodiment of
the present invention includes the steps of obtaining a difference value
and index information, entropy-decoding the index information,
identifying an entropy table corresponding to the entropy-decoded index
information, and entropy-decoding the difference value using the
identified entropy table.

[0504]Subsequently, a reference value corresponding to a plurality of data
and the decoded difference value are used to obtain the data. In this
case, the reference value may include a pilot reference value or a
difference reference value.

[0505]The index information is entropy-decoded using an index dedicated
entropy table. And, the entropy table is classified according to a type
of each of a plurality of the data.

[0506]The data are parameters, and the method further includes the step of
reconstructing an audio signal using the parameters.

[0507]In case of entropy-decoding the difference value, 2D entropy
decoding is performed on the difference value using the entropy table.

[0508]Moreover, the method further includes the steps of obtaining the
reference value and entropy-decoding the reference value using the
entropy table dedicated to the reference value.

[0509]An apparatus for processing a signal according to another embodiment
of the present invention includes an inputting part obtaining a
difference value and index information, an index decoding part
entropy-decoding the index information, a table identifying part
identifying an entropy table corresponding to the entropy-decoded index
information, and a data decoding part entropy-decoding the difference
value using the identified entropy table.

[0510]The apparatus further includes a data obtaining part obtaining data
using a reference value corresponding to a plurality of data and the
decoded difference value.

[0511]A method of processing a signal according to a further embodiment of
the present invention includes the steps of generating a difference value
using a reference value corresponding to a plurality of data and the
data, entropy-encoding the difference value using an entropy table, and
generating index information to identify the entropy table.

[0512]And, the method further includes the steps of entropy-encoding the
index information and transferring the entropy-encoded index information
and the difference value.

[0513]And, an apparatus for processing a signal according to a further
embodiment of the present invention includes a value generating part
generating a difference value using a reference value corresponding to a
plurality of data and the data, a value encoding part entropy-encoding
the difference value using an entropy table, an information generating
part generating index information to identify the entropy table, and an
index encoding part entropy-encoding the index information. And, the
apparatus further includes an information outputting part transferring
the entropy-encoded index information and the difference value.

[Data Structure]

[0514]A data structure including various kinds of information associated
with the aforesaid data coding, grouping and entropy coding according to
the present invention is explained as follows.

[0515]FIG. 23 is a hierarchical diagram of a data structure according to
the present invention.

[0516]Referring to FIG. 23, a data structure according to the present
invention includes a header 100 and a plurality off frames 101 and 102.
Configuration information applied to the lower frames 101 and 102 in
common is included in the header 100. And, the configuration information
includes grouping information utilized for the aforesaid grouping.

[0517]For instance, the grouping information includes a first time
grouping information 100a, a first frequency grouping information 100b
and a channel groping information 100c.

[0518]Besides, the configuration information within the header 100 is
called `main configuration information` and an information portion
recorded in the frame is called `payload`.

[0519]In particular, a case of applying the data structure of the present
invention to audio spatial information is explained in the following
description for example.

[0520]First of all, the first time grouping information 100a within the
header 100 becomes `bsFrameLength` field that designates a number of
timeslots within a frame.

[0521]The first frequency grouping information 100b becomes `bsFreqRes`
field that designates a number of parameter bands within a frame.

[0522]The channel grouping information 100c means `OttmodeLFE-bsOttBands`
field and `bsTttDualmode-bsTttBandsLow` field. The
`OttmodeLFE-bsOttBands` field is the information designating a number of
parameter bands applied to LFE channel. And, the
`bsTttDualmode-bsTttBandsLow` field is the information designating a
number of parameter bands of a low frequency band within a dual mode
having both low and high frequency bands. Ye, the
`bsTttDualmode-bsTttBandsLow` field can be classified not as channel
grouping information but as frequency grouping information.

[0523]Each of the frames 101 and 102 includes a frame information (Frame
Info) 101a applied to all groups within a frame in common and a plurality
of groups 101b and 101c.

[0524]The frame information 101a includes a time selection information
103a, a second time grouping information 103b and a second frequency
grouping information 103c. Besides, the frame information 101a is called
`sub-configuration information` applied to each frame.

[0525]In detail, a case of applying the data structure of the present
invention to audio spatial information is explained in the following
description, for example.

[0526]The time selection information 103a within the frame information
101a includes `bsNumParamset` field, `bsParamslot` field and `bsDataMode`
filed.

[0527]The `bsNumParamset` field is information indicating a number of
parameter sets existing within an entire frame.

[0528]And, the `bsParamslot` field is information designating a position
of a timeslot where a parameter set exists.

[0529]Moreover, the `bsDataMode` field is information designating an
encoding and decoding processing method of each parameter set.

[0530]For instance, in case of `bsDataMode=0` (e.g., default mode) of a
specific parameter set, a decoding part replaces the corresponding
parameter set by a default value.

[0531]In case of `bsDataMode=1` (e.g., previous mode) of a specific
parameter set, a decoding part maintains a decoding value of a previous
parameter set.

[0532]In case of `bsDataMode=2` (e.g., interpolation mode) of a specific
parameter set, a decoding part calculates a corresponding parameter set
by interpolation between parameter sets.

[0533]Finally, in case of `bsDataMode=3` (e.g., read mode) of a specific
parameter set, it means that coding data for a corresponding parameter
set is transferred. So, a plurality of the groups 101b and 101c within a
frame are groups configured with data transferred in case of
`bsDataMode=3` (e.g., read mode). Hence, the encoding part decodes data
with reference to coding type information within each of the groups.

[0534]A signal processing method and apparatus using the `bsDataMode`
field according to one embodiment of the present invention are explained
in detail as follows.

[0535]A method of processing a signal using the `bsDataMode` field
according to one embodiment of the present invention includes the steps
of obtaining mode information, obtaining a pilot reference value
corresponding to a plurality of data and a pilot difference value
corresponding to the pilot reference value according to data attribute
indicated by the mode information, and obtaining the data using the pilot
reference value and the pilot difference value.

[0536]In this case, the data are parameters, and the method further
includes the step of reconstructing an audio signal using the parameters.

[0538]The mode information further includes at least one of a default
mode, a previous mode and an interpolation mode.

[0539]And, the pilot difference value is obtained per group band.

[0540]Moreover, the signal processing method uses a first parameter (e.g.,
dataset) to identify a number of the read modes and a second parameter
(e.g., setidx) to obtain the pilot difference value based on the first
variable.

[0541]An apparatus for processing a signal using the `bsDataMode` field
according to one embodiment of the present invention includes an
information obtaining part obtaining mode information, a value obtaining
part obtaining a pilot reference value corresponding to a plurality of
data and a pilot difference value corresponding to the pilot reference
value according to data attribute indicated by the mode information, and
a data obtaining part obtaining the data using the pilot reference value
and the pilot difference value.

[0542]And, the information obtaining part, the value obtaining part and
the data obtaining part are provided within the aforesaid data decoding
part 91 or 92.

[0543]A method of processing a signal using the `bsDataMode` field
according to another embodiment of the present invention includes the
steps of generating mode information indicating attribute of data,
generating a pilot difference value using a pilot reference value
corresponding to a plurality of data and the data, and transferring the
generated difference value. And, the method further includes the step of
encoding the generated difference value.

[0544]An apparatus for processing a signal using the `bsDataMode` field
according to another embodiment of the present invention includes an
information generating part generating mode information indicating
attribute of data, a value generating part generating a pilot difference
value using a pilot reference value corresponding to a plurality of data
and the data, and an outputting part transferring the generated
difference value. And, the value generating part is provided within the
aforesaid data encoding part 31 or 32.

[0545]The second time grouping information 103b within the frame
information 101a includes `bsDatapair` field. The `bsDatapair` field is
information that designates a presence or non-presence of a pair between
data sets designated by the `bsDataMode=3`. In particular, two data sets
are grouped into one group by the `bsDatapair` field.

[0546]The second frequency grouping information within the frame
information 101a includes `bsFreqResStride` field. The `bsFreqResStride`
field is the information to second-group the parameter bad first-grouped
by the `bsFreqRes` field as the first frequency grouping information
100b. Namely, a data band is generated by binding parameters amounting to
a stride designated by the `bsFreqResStride` field. So, parameter values
are given per the data band.

[0548]In detail, a case of applying the data structure of the present
invention to audio spatial information is explained as follows, for
example.

[0549]First of all, the data coding type information 104a within each of
the groups 101b and 101c includes `bsPCMCoding` field, `bsPilotCoding`
field, `bsDiffType` field and `bdDifftimeDirection` field.

[0550]The `bsPCMCoding` field is information to identify whether data
coding of the corresponding group is PCM scheme or DIFF scheme.

[0551]Only if the `bsPCMCoding` field designates the PCM scheme, a
presence or non-presence of the PBC scheme is designated by the
`bsPilotCoding` field.

[0552]The `bsDifftype` field is information to designate a coding
direction in case that DIFF scheme is applied. And, the `bsDiffType`
field designates either `DF: DIFF-FREQ` or `DT: DIFF-TIME`.

[0553]And, the `bsDiffTimeDirection` field is information to designate
whether a coding direction on a time axis is `FORWARD` or `BACKWARD` in
case that the `bsDiffType` field is `DT`.

[0554]The entropy coding type information 104b within each of the groups
101b and 101c includes `bsCodingScheme` field and `bsPairing` field.

[0555]The `bsCodingScheme` field is the information to designate whether
entropy coding is 1D or 2D.

[0556]And, the `bsPairing` field is the information whether a direction
for extracting two indexes is a frequency direction (FP: Frequency
Pairing) or a time direction (TP: Time Pairing) in case that the
`bsCodingScheme` field designates `2D`.

[0557]The codeword 104c within each of the groups 101b and 101c includes
`bsCodeW` field. And, the `bsCodeW` field designates a codeword on a
table applied for entropy coding. So, most of the aforesaid data become
targets of entropy coding. In this case, they are transferred by the
`bsCodeW` field. For instance, a pilot reference value and LAV Index
value of PBC coding, which become targets of entropy coding, are
transferred by the `bsCodeW` field.

[0558]The side data 104d within each of the groups 101b and 101c includes
`bsLsb` field and `bsSign` field. In particular, the side data 104d
includes other data, which are entropy-coded not to be transferred by the
`bsCodeW` field, as well as the `bsLsb` field and the `bsSign` field.

[0559]The `bsLsb` field is a field applied to the aforesaid partial
parameter and is the side information transferred only if a data type is
`CPC` and in case of non-coarse quantization.

[0560]And, the `bsSign` field is the information to designate a sign of an
index extracted in case of applying 1D entropy coding.

[0561]Moreover, data transferred by PCM scheme are included in the side
data 104d.

[0562]Features of the signal processing data structure according to the
present invention are explained as follows.

[0563]First of all, a signal processing data structure according to the
present invention includes a payload part having at least one of data
coding information including pilot coding information at least per a
frame and entropy coding information and a header part having main
configuration information for the payload part.

[0564]The main configuration information includes a first time information
part having time information for entire frames and a first frequency
information part having frequency information for the entire frames.

[0565]And, the main configuration information further includes a first
internal grouping information part having information for
internal-grouping a random group including a plurality of data per frame.

[0566]The frame includes a first data part having at least one of the data
coding information and the entropy coding information and a frame
information part having sub-configuration information for the first data
part.

[0567]The sub-configuration information includes a second time information
part having time information for entire groups. And, the
sub-configuration information further includes an external grouping
information part having information for external grouping for a random
group including a plurality of data per the group. Moreover, the
sub-configuration information further includes a second internal grouping
information part having information for internal-grouping the random
group including a plurality of the data.

[0568]Finally, the group includes the data coding information having
information for a data coding scheme, the entropy coding information
having information for an entropy coding scheme, a reference value
corresponding to a plurality of data, and a second data part having a
difference value generated using the reference value and the data.

[Application to Audio Coding (MPEG Suround)]

[0569]An example of unifying the aforesaid concepts and features of the
present invention is explained as follows.

[0570]FIG. 24 is a block diagram of an apparatus for audio compression and
recovery according to one embodiment of the present invention.

[0571]Referring to FIG. 24, an apparatus for audio compression and
recovery according to one embodiment of the present invention includes an
audio compression part 105˜400 and an audio recovery part
500˜800.

[0572]The audio compression part 105˜400 includes a downmixing part
105, a core coding part 200, a spatial information coding part 300 and a
multiplexing part 400.

[0573]And, the downmixing part 105 includes a channel downmixing part 110
and a spatial information generating part 120.

[0574]In the downmixing part 105, inputs of the channel downmixing part
110 are an audio signal of N multi-channels X1, X2, . . . ,
XN) and the audio signal.

[0575]The channel downmixing part 110 outputs a signal downmixed into
channels of which number is smaller than that of channels of the inputs.

[0576]An output of the downmixing part 105 is downmixed into one or two
channels, a specific number of channels according to a separate
downmixing command, or a specific number of channels preset according to
system implementation.

[0577]The core coding part 200 performs core coding on the output of the
channel downmixing part 110, i.e., the downmixed audio signal. In this
case, the core coding is carried out in a manner of compressing an input
using various transform schemes such as a discrete transform scheme and
the like.

[0578]The spatial information generating part 120 extracts spatial
information from the multi-channel audio signal. The spatial information
generating part 120 then transfers the extracted spatial information to
the spatial information coding part 300.

[0579]The spatial information coding part 300 performs data coding and
entropy coding on the inputted spatial information. The spatial
information coding part 300 performs at least one of PCM, PBC and DIFF.
In some cases, the spatial information coding part 300 further performs
entropy coding. A decoding scheme by a spatial information decoding part
700 can be decided according to which data coding scheme is used by the
spatial information coding part 300. And, the spatial information coding
part 300 will be explained in detail with reference to FIG. 25 later.

[0580]An output of the core coding part 200 and an output of the spatial
information coding part 300 are inputted to the multiplexing part 400.

[0581]The multiplexing part 400 multiplexes the two inputs into a
bitstream and then transfers the bitstream to the audio recovery part 500
to 800.

[0582]The audio recovery part 500 to 800 includes a demultiplexing part
500, a core decoding part 600, a spatial information decoding part 700
and a multi-channel generating part 800.

[0583]The demultiplexing part 500 demultiplexes the received bitstream
into an audio part and a spatial information part. In this case, the
audio part is a compressed audio signal and the spatial information part
is a compressed spatial information.

[0584]The core decoding part 600 receives the compressed audio signal from
the demultiplexing part 500. The core decoding part 600 generates a
downmixed audio signal by decoding the compressed audio signal.

[0585]The spatial information decoding part 700 receives the compressed
spatial information from the demultiplexing part 500. The spatial
information decoding part 700 generates the spatial information by
decoding the compressed spatial information.

[0586]In doing so, identification information indicating various grouping
information and coding information included in the data structure shown
in FIG. 23 is extracted from the received bitstream. A specific decoding
scheme is selected from at least one or more decoding schemes according
to the identification information. And, the spatial information is
generated by decoding the spatial information according to the selected
decoding scheme. In this case, the decoding scheme by the spatial
information decoding part 700 can be decided according to what data
coding scheme is used by the spatial information coding part 300. And,
the spatial information decoding part 700 is will be explained in detail
with reference to FIG. 26 later.

[0587]The multi-channel generating part 800 receives an output of the core
coding part 600 and an output of the spatial information decoding part
160. The multi-channel generating part 800 generates an audio signal of N
multi-channels Y1, Y2, . . . , YN from the two received
outputs.

[0588]Meanwhile, the audio compression part 105˜400 provides an
identifier indicating what data coding scheme is used by the spatial
information coding part 300 to the audio recovery part 500˜800. To
prepare for the above-explained case, the audio recovery part
500˜800 includes a means for parsing the identification
information.

[0589]So, the spatial information decoding part 700 decides a decoding
scheme with reference to the identification information provided by the
audio compression part 105˜400. Preferably, the means for parsing
the identification information indicating the coding scheme is provided
to the spatial information decoding part 700.

[0590]FIG. 25 is a detailed block diagram of a spatial information
encoding part according to one embodiment of the present invention, in
which spatial information is named a spatial parameter.

[0591]Referring to FIG. 25, a coding part according to one embodiment of
the present invention includes a PCM coding part 310, a DIFF
(differential coding) part 320 and a Huffman coding part 330. The Huffman
coding part 330 corresponds to one embodiment of performing the aforesaid
entropy coding.

[0592]The PCM coding part 310 includes a grouped PCM coding part 311 and a
PCB part 312. The grouped PCM coding part 311 PCM-codes spatial
parameters. In some cases, the grouped PCM coding part 311 is able to
PCM-codes spatial parameters by a group part. And, the PBC part 312
performs the aforesaid PBC on spatial parameters.

[0594]In particular, in the present invention, one of the grouped PCM
coding part 311, the PBC part 312 and the DIFF part 320 selectively
operates for coding of spatial parameters. And, its control means is not
separately shown in the drawing.

[0595]The PBC executed by the PBC part 312 has been explained in detail in
the foregoing description, of which explanation will be omitted in the
following description.

[0596]For another example of PBC, PBC is once performed on spatial
parameters. And, the PBC can be further performed N-times (N>1) on a
result of the first PBC. In particular, the PBC is at least once carried
out on a pilot value or difference values as a result of performing the
first PBC. In some cases, it is preferable that the PBC is carried out on
the difference values only except the pilot value since the second PBC.

[0597]The DIFF part 320 includes a DIFF_FREQ coding part 321 performing
DIFF_FREQ on a spatial parameter and DIFF_TIME coding parts 322 and 323
performing DIFF_TIME on spatial parameters.

[0598]In the DIFF part 320, one selected from the group consisting of the
DIFF_FREQ coding part 321 and the DIFF_TIME coding parts 322 and 323
carries out the processing for an inputted spatial parameter.

[0599]In this case, the DIFF_TIME coding parts are classified into a
DIFF_TIME_FORWARD part 322 performing DIFF_TIME_FORWARD on a spatial
parameter and a DIFF_TIME_BACKWARD part 323 performing DIFF_TIME_BACKWARD
on a spatial parameter.

[0600]In the DIFF_TIME coding parts 322 and 323, a selected one of the
DIFF_TIME_FORWARD part 322 and the DIFF_TIME_BACKWARD 323 carries out a
data coding process on an inputted spatial parameter. Besides, the DIFF
coding performed by each of the internal elements 321, 322 and 323 of the
DIFF part 320 has been explained in detail in the foregoing description,
of which explanation will be omitted in the following description.

[0601]The Huffman coding part 330 performs Huffman coding on at least one
of an output of the PBC part 312 and an output of the DIF part 320.

[0602]The Huffman coding part 330 includes a 1-dimension Huffman coding
part (hereinafter abbreviated HUFF--1D part) 331 processing data to
be coded and transmitted one by one and a 2-dimension Huffman coding part
(hereinafter abbreviated HUFF--2D parts 332 and 333 processing data
to be coded and transmitted by a unit of two combined data.

[0603]A selected one of the HUFF--1D part 331 and the HUFF--2D
parts 332 and 333 in the Huffman coding part 330 performs a Huffman
coding processing on an input.

[0604]In this case, the HUFF--2D parts 332 and 333 are classified
into a frequency pair 2-Dimension Huffman coding part (hereinafter
abbreviated HUFF--2D_FREQ_PAIR part) 332 performing Huffman coding
on a data pair bound together based on a frequency and a time pair
2-Dimension Huffman coding part (hereinafter abbreviated
HUFF--2D_TIME_PAIR part) 333 performing Huffman coding on a data
pair bound together based on a time.

[0605]In the HUFF--2D parts 332 and 333, a selected one of the
HUFF--2D_FREQ_PAIR part 332 and the HUFF--2D_TIME_PAIR part 333
performs a Huffman coding processing on an input.

[0606]Huffman coding performed by each of the internal elements 331, 332
and 333 of the Huffman coding part 330 will explained in detail in the
following description.

[0607]Thereafter, an output of the Huffman coding part 330 is multiplexed
with an output of the grouped PCM coding part 311 to be transferred.

[0608]In a spatial information coding part according to the present
invention, various kinds of identification information generated from
data coding and entropy coding are inserted into a transport bitstream.
And, the transport bitstream is transferred to a spatial information
decoding part shown in FIG. 26.

[0609]FIG. 26 is a detailed block diagram of a spatial information
decoding part according to one embodiment of the present invention.

[0610]Referring to FIG. 26, a spatial information decoding part receives a
transport bitstream including spatial information and then generates the
spatial information by decoding the received transport bitstream.

[0611]A spatial information decoding part 700 includes an identifier
extracting (flags parsing part) 710, a PCM decoding part 720, a Huffman
decoding part 730 and a differential decoding part 740.

[0612]The identifier parsing part 710 of the spatial information decoding
part extracts various identifiers from a transport bitstream and then
parses the extracted identifiers. This means that various kinds of the
informations mentioned in the foregoing description of FIG. 23 are
extracted.

[0613]The spatial information decoding part is able to know what kind of
coding scheme is used for a spatial parameter using an output of the
identifier parsing part 710 and then decides a decoding scheme
corresponding to the recognized coding scheme. Besides, the execution of
the identifier parsing part 710 can be performed by the aforesaid
demultiplexing part 500 as well.

[0614]The PCM decoding part 720 includes a grouped PCM decoding part 721
and a pilot based decoding part 722.

[0615]The grouped PCM decoding part 721 generates spatial parameters by
performing PCM decoding on a transport bitstream. In some cases, the
grouped PCM decoding part 721 generates spatial parameters of a group
part by decoding a transport bitstream.

[0616]The pilot based decoding part 722 generates spatial parameter values
by performing pilot based decoding on an output of the Huffman decoding
part 730. This corresponds to a case that a pilot value is included in an
output of the Huffman decoding part 730. For separate example, the pilot
based decoding part 722 is able to include a pilot extracting part (not
shown in the drawing) to directly extract a pilot value from a transport
bitstream. So, spatial parameter values are generated using the pilot
value extracted by the pilot extracting part and difference values that
are the outputs of the Huffman decoding part 730.

[0617]The Huffman decoding part 730 performs Huffman decoding on a
transport bitstream. The Huffman decoding part 730 includes a 1-Dimension
Huffman decoding part (hereinafter abbreviated HUFF--1D decoding
part) 731 outputting a data value one by one by performing 1-Dimension
Huffman decoding on a transport bitstream and 2-Dimension Huffman
decoding parts (hereinafter abbreviated HUFF--2D decoding parts) 732
and 733 outputting a pair of data values each by performing 2-Dimension
Huffman decoding on a transport bitstream.

[0618]The identifier parsing part 710 extracts an identifier (e.g.,
`bsCodingScheme`) indicating whether a Huffman decoding scheme indicates
HUFF--1D or HUFF--2D from a transport bitstream and then
recognizes the used Huffman coding scheme by parsing the extracted
identifier. So, either HUFF--1D or HUFF--2D decoding
corresponding to each case is decided as a Huffman decoding scheme.

[0620]In case that the Huffman coding scheme is HUFF--2D in a
transport bit stream, the identifier parsing part 710 further extracts an
identifier (e.g., `bsParsing`) indicating whether the HUFF--2D
scheme is HUFF--2D_FREQ_PAIR or HUFF--2D_TIME_PAIR and then
parses the extracted identifier. So, the identifier parsing part 710 is
able to recognize whether two data configuring one pair are bound
together based on frequency or time. And, one of frequency pair
2-Dimension Huffman decoding (hereinafter abbreviated
HUFF--2D_FREQ_PAIR decoding) and time pair 2-Dimension Huffman
decoding (hereinafter abbreviated HUFF--2D_TIME_PAIR decoding)
corresponding to the respective cases is decided as the Huffman decoding
scheme.

[0621]In the HUFF--2D decoding parts 732 and 733, the
HUFF--2D_FREQ_PAIR part 732 performs HUFF--2D_FREQ_PAIR
decoding and the HUFF--2D_TIME_PAIR part 733 performs
HUFF--2D_FREQ_TIME decoding.

[0622]An output of the Huffman decoding part 730 is transferred to the
pilot based decoding part 722 or the differential decoding part 740 based
on an output of the identifier parsing part 710.

[0623]The differential decoding part 740 generates spatial parameter
values by performing differential decoding on an output of the Huffman
decoding part 730.

[0624]The identifier parsing part 710 extracts an identifier (e.g.,
`bsDiffType`) indicating whether a DIFF scheme is DIF_FREQ or DIF_TIME
from a transport bit stream from a transport bitstream and then
recognizes the used DIFF scheme by parsing the extracted identifier. So,
one of the DIFF_FREQ decoding and DIFF_TIME decoding corresponding to the
respective cases is decided as a differential decoding scheme.

[0626]In case that the DIFF scheme is DIFF_TIME, the identifier parsing
part 710 further extracts an identifier (e.g., `bsDiffTimeDirection`)
indicating whether the DIFF_TIME is DIFF_TIME_FORWARD or
DIFF_TIME_BACKWARD from a transport bitstream and then parses the
extracted identifier.

[0627]So, it is able to recognize whether an output of the Huffman
decoding part 730 is a difference value between current data and former
data or a difference value between the current data and next data. One of
DIFF_TIME_FORWARD decoding and DIFF_TIME_BACKWARD decoding corresponding
to the respective cases is decided as a DIFF_TIME scheme.

[0629]A procedure for deciding a Huffman decoding scheme and a data
decoding scheme based on an output of the identifier parsing part 710 in
the spatial information decoding part is explained as follows.

[0630]For instance, the identifier parsing part 710 reads a first
identifier (e.g., `bsPCMCoding`) indicating which one of PCM and DIFF is
used in coding a spatial parameter.

[0631]If the first identifier corresponds to a value indicating PCM, the
identifier parsing part 710 further reads a second identifier (e.g.,
`bsPilotCoding`) indicating which one of PCM and PBC is used for coding
of a spatial parameter.

[0632]If the second identifier corresponds to a value indicating PBC, the
spatial information decoding part performs decoding corresponding to the
PBC.

[0633]If the second identifier corresponds to a value indicating PCM, the
spatial information decoding part performs decoding corresponding to the
PCM.

[0634]On the other hand, if the first identifier corresponds to a value
indicating DIFF, the spatial information decoding part performs a
decoding processing that corresponds to the DIFF.

MODE FOR INVENTION

[0635]Accordingly, various embodiments of the present invention are
explained together with the aforesaid embodiments of the best mode.

INDUSTRIAL APPLICABILITY

[0636]Accordingly, the grouping, data coding and entropy coding of the
present invention are applicable to various fields and products.

[0637]And, the present invention is applicable to a medium that stores
data to which at least one feature of the present invention is applied.

[0638]While the present invention has been described and illustrated
herein with reference to the preferred embodiments thereof, it will be
apparent to those skilled in the art that various modifications and
variations can be made therein without departing from the spirit and
scope of the invention. Thus, it is intended that the present invention
covers the modifications and variations of this invention that come
within the scope of the appended claims and their equivalents.